Paradox

by CCC

Rating: everyone
Tags: My Little Pony: Friendship is Magic, Adventure, Crossover, Doctor Whooves, Twilight Sparkle
Length: 16102

When a visitor from the future appears out of nowhere in Twilight's new castle, he triggers a series of events that sends Twilight back and forth through history...

When a visitor from the future appears out of nowhere in Twilight's new castle, he triggers a series of events that sends Twilight back and forth through history...

For other takes on the same prompt, see Stopped Clock, by Carabas, and From Forever, With Love by Monokeras

Published 2015-01-16 18:40:02 UTC
Last updated 2015-04-25 10:14:08 UTC

The Time Traveller

Lightning crackled through Twilight's new castle. It skittered over the crystal walls, ran electric fingers over the thrones, crackled on the table in the centre of the room.

Twilight stared at the display. She'd seen it before, and had made a plan for just this eventuality. She felt the wind through her mane as the air in the room moved and shifted, swirling around a central point. She averted her eyes as that point glowed, releasing light from the temporal differential. And she looked back at just the right moment to see a pony appear from nothing, right in the centre of the table.

She really hadn't been expecting that particular pony, though.

“Time Turner?” she asked. The brown stallion with the hourglass cutie mark was a well-known Ponyville resident; he repaired clocks and watches, had a truly excellent sense of timing, and – importantly – he was an earth pony, and thus unable to cast magic on his own; including the time travel spell that Twilight had just seen him arrive with.

He held out one hoof to cover Twilight's mouth, leaving a ring of brown hoof polish. Twilight noticed some sort of device wrapped around his forelimb; something with a tiny keyboard on it, buttons that looked far too small to use with a hoof. “No time to explain. I've only got a few minutes to deliver my message.”

Twilight nodded. 'Keep Quiet And Let The Time Traveller Talk' was, after all, the next item in her plan.

“It's going to be a bit cryptic,” said the stallion, lowering his hoof, “for which I apologise; but trust me when I say that this message is of vital importance.”

Twilight nodded again.

The stallion cleared his throat and looked into the distance. “Beware the Sun.” he said; and then “You will be betrayed.”

“I'll be what?” asked Twilight.

“Betrayed,” said the stallion. “Turned on. Attacked, by someone very close to you.”

“That's ridiculous!” said Twilight. “None of my friends would -”

The stallion put a hoof on Twilight's mouth again, rubbing off a little more hoof polish to reveal the grey beneath it. “No time to argue,” he said, the wind around him already picking up as his time spell began to wear off. “Just remember – whatever else happens, whatever you think will happen, no matter what – do not, I repeat, do not tell –”

There was the sound of an explosion in reverse as the stallion vanished from the Castle of Friendship.

Twilight stared for a long moment at the spot where he'd vanished.

“Don't tell who?” she asked, mystified.

“Twilight?” asked Spike, stepping into the room with a feather duster in one claw. “Are you alright? Did something happen? I heard a noise...”

“Well,” began Twilight, and then she stopped. ”Don't tell” she thought. Could it have been – don't tell Spike? ...no, surely not. Still, betrayed? By someone close to me? Who's closer than than Spike?

“Twilight?” asked Spike again.

“Ummmm.... nothing!” squeaked Twilight. “Absolutely nothing happened at all!”

“Really,” said Spike, folding his arms. “Well, 'nothing' appears to have left two circles of hoof polish on your muzzle.”

“Oh, um, er.... I've got to go!” Twilight said, running for the door.

Spike shook his head and sighed. He took his feather duster and went to dust off the table. He took one look at it, sighed again, and went to go and fetch a bottle of hoof polish remover.

Time Turner

“Come in!” called Time Turner. He turned to greet the potential customer, and his smile broadened at the sight of the local royalty. “Princess Sparkle! What can I do for you today?”

“Who mustn't I tell?” asked Twilight, marching into the clock shop.

Time Turner frowned.

“Who mustn't I tell?” Twilight marched into the shop, forcing Time Turner to back away. “Who mustn't I tell?”

“Ummm...” Time Turner pointed at Twilight's muzzle. “You've got some... looks like hoof polish...”

“WHO MUSTN'T I TELL?” Twilight's voice echoed through the shop, making the clocks rattle and vibrate; a grandfather clock trembled, a cuckoo popped out of another clock a full ten minutes early, and the brass watch on the windowsill slid a little closer to the edge.

Time Turner took a deep breath. “I HAVE NO IDEA WHAT YOU'RE TALKING ABOUT!” he yelled back. The cuckoo clock went off again, the grandfather clock missed another tick, and the brass watch balanced precariously on the edge of the windowsill.

“Oh,” said Twilight, rocking back slightly on her heels. “Um. Of... of course you wouldn't. I... um. I... I don't actually know if you can help me, but I don't know whether I can even talk about this to anypony else, so...”

TimeTurner raised an eyebrow at that. “Princess Twilight Sparkle,” he said. “You're the Princess of Friendship. You have a group of close friends – legendarily close friends – whose friendship is so strong that it has quite literally saved Equestria on numerous occasions. And now you – you of all ponies – are telling me – who you hardly know – that there's something you can't discuss with them but you can discuss with me?”

Twilight looked down at her hooves. “Um,” she said. “When you put it like that it sounds really stupid.”

“Not in the least,” said Time Turner. “But it's certainly piqued my curiousity. Tell you what, how about I make some tea, and I'm sure I've got some crumpets somewhere, and then we can discuss, well, whatever this is?”

“Um. Sure. Thanks.” Twilight smiled slightly, and sat down.

Time Turner trotted into the back room, and there was shortly the sounds of tea being prepared. “I should warn you, though,” he called out, “I'm not much into saving the world, myself. Personal peril I prefer to avoid, where possible.”

“Heh,” said Twilight. “What about saving the world when you're not putting yourself in peril?”

“Oh, I'm fully in favour of that,” he called out. “I mean, the world's where I keep my shop, after all. I don't exactly go looking for opportunities, and I'm not sure I wouldn't panic and run when the time comes, but I'm sure I can at least make a go at it if the opportunity falls in front of me.”

“What about time travel?” asked Twilight.

There was a crash of a dropped teacup, and Time Turner poked his head out of the back room. “Have you been reading my diary?” he asked.

“What?” said Twilight. “No!”

“Hmmmm.” Time Turner retreated back into the back room, and began to sweep up the teacup. “It's all science fiction, anyway. Time travel, daleks, cybermen, Shakespeare, humanity... I mean, it's ridiculous, that's what it is. Imagine, a race without any magic at all, making machines that can think for them!”

“I don't know about the rest of what you said,” said Twilight, “but time travel is possible. I mean, not for a race without magic; but there are such things as time spells.”

“Ridiculous,” insisted Time Turner. “What would happen if you went back and killed your own grandfather? Before your father was born, I mean.”

“You can't,” said Twilight, promptly. “You can go back maybe a week. Once.”

“You can still trigger a paradox with that.” Time Turner trotted back into the shop, carrying a tea tray on his back. “What if you go back and prevent whatever caused you to want to go back in the first place? Then you wouldn't go back, so you wouldn't prevent it, so you would go back, and so...” He paused to put the tea tray on a table. “You see what I mean?” he asked. “The only reasonable course of action is that you go back and fail to prevent whatever you went back to prevent in the first place.” He picked up a pair of sugar tongs in his mouth and asked “One lump or two?”

“Two, please,” said Twilight. “Thank you. Well... one other possibility is that you go back in time and end up causing yourself to want to... oh dear...”

“I suppose that is also a theoretical possibility,” admitted Time Turner. “A loop that causes itself, the one end joining seamlessly onto the other. But then what could cause such a loop? It happens because it happens; there is no original cause, so to speak. I doubt it could ever happen in practice. Crumpet?”

“Thank you. It... that's what happened the first time I had anything to do with time travel I came back – to try to warn myself about something – but never quite got the warning out before the spell wore off. I spent an entire – very stressful – week trying to prevent any possible disaster; and then, when a disaster failed to materialise, I went back to try to tell myself not to worry about potential future disasters... but didn't get the warning out before the spell ran out.”

“And there was absolutely no disaster at all in that period?” asked Time Turner.

“Well, it later turned out that Tirek had taken the opportunity to break out of Tartarus during that week,” admitted Twilight. “But I didn't find out about that for months.”

“I see,” said Time Turner. “But if that happened months ago, then surely it's not why you burst into my shop this morning?”

“No,” said Twilight, taking a sip of tea. “This morning, I met another time traveller.”

“Your future self again?” asked Time Turner.

“No,” said Twilight. “You.”

There was a long silence. Then Time Turner put down his teacup. “I see,” he said. “I'm an Earth pony. How could I have cast the spell?”

“I don't know,” admitted Twilight. “Maybe somepony cast the spell on you? Maybe I did – I mean, will. It's not exactly designed to be cast on somepony else, but maybe I can figure out a way...”

“That hoof polish on your muzzle,” said Time Turner.

“Yes?” asked Twilight.

“It's the same colour as my hooves. Was that the future me? Holding a hoof over your mouth to get you to keep quiet, perhaps?”

Twilight nodded. “Yes!” she said.

“I don't wear hoof polish,” said Time Turner, firmly. He handed her a napkin. “You might want to wipe it off, by the way.”

“Oh. Thanks.”

“You say the spell wears off?” asked Time Turner. “Catapulting whoever back to the future, I'm guessing?”

“Yes,” said Twilight, nodding again as she wiped her muzzle.

“Then why did the hoof polish stay?” asked Time Turner.

Twilight blinked, and stared at the brown stain on the napkin. “Um,” she said. “I... don't know. Time magic is a terribly underexplored branch of magical theory...”

“Hmmm,” said Time Turner.

“I can tell you what future you said,” offers Twilight.

“Better not,” insisted Time Turner. “If you tell me, then I'm obliged to repeat the same words if I ever go back, even if it's just meaningless noises. If you actually want what future me told you to mean anything, then I shouldn't know what I have to say in advance.”

“So... future you wore hoof polish because you saw hoof polish on my muzzle now?” asked Twilight.

“It's possible,” mused Time Turner. “It's like your original time travel – a loop with no external cause. Ugh, I hate hoof polish.” He shuddered.

And twelve-o'clock hit.

Every clock bonged, chimed, rang, or cuckooed. The grandfather clock was a moment late, the malfunctioning cuckoo clock cuckooed thirteen times. The entire shop vibrated slightly; the tea sloshed in the cups, a crumpet fell from the top of the pile, and the brass watch on the windowsill finally fell off the edge.

Twilight caught it in her magic, and passed it to Time Turner. “Here you go,” she said.

“Thanks,” said Time Turner, placing it on the table. “Wouldn't have mattered if you didn't catch it, anyway,” he added. “That watch hasn't worked in years.”

Twilight blinked, and stared. “You repair clocks and watches for a living,” she said.

“Yes?” said Time Turner.

“And a hobby.”

“Yes...”

“I've known you to repair Rarity's clock after Sweetie Belle managed to gum up the insides with tree sap and then tried to get a cutie mark in clock repair.”

“Well, I had to replace most of the insides, but...”

“It took you two weeks,” said Twilight.

“Um, yes?”

“And you've had that handsome brass watch for years and you've never quite got around to replacing the mechanism?”

“Hmmm.” Time Turner looked at the watch. “Well, when you put it like that,” he admitted, “it does sound a little odd.”

Time Turner opened the watch and looked inside.

The Doctor

Time Turner staggered back as the light shining out of the brass watch hit him in the face. Then he staggered forward again, collapsing, his head thumping onto the table, The side of his face hit a teaspoon, which pinwheeled up into the air, bounced off a rafter, and landed somewhere among the clocks.

“Time Turner?” Twilight teleported to his side, using her telekinesis to hold him up. “Are you alright?”

The brown stallion blinked, twice.

“How many hooves am I holding up?” asked Twilight.

The stallion looked at the napkin, still covered with hoof polish, then back at Twilight. “How are you not dead yet?” he asked.

“...what?”

“Oh, and you're holding up one hoof.”

“What do you mean, why am I not dead yet?”

“That hoof polish.” The stallion nodded at the napkin. “It's been mixed with basilisk venom. Absolutely deadly, swift-acting, one of the few poisons that can work on even alicorns. It should have killed you in the time we were talking here.”

“What?”

“Only one antidote. Potassium breaks it down. I don't know how you survived this long without your insides melting, but you need to teleport to the market, right now, buy all the bananas you can get your hooves on, and eat them!”

“What?”

“Bananas! Now! Or you'll die!”

“I just -”

“No time!” yelled the stallion. “Bananas! And bring some with you to the castle! I'll meet you there! If there's more of this hoof polish there, the basilisk venom could have got anypony!”

Twilight immediately vanished in a flash of purple.

* * *

“What's with you and bananas today, Pinkie?” asked Spike, trying to fend off the pink party pony.

“They're good for you!” said Pinkie, trying to stuff another banana into Spike's mouth. “And Twilight told me you need lots of potassium!”

“Look, I've already eaten half a dozen of the things!” objected Spike. “I've got no more room for any more!”

There was a flash of purple, and Twilight appeared, along with a large bunch of bananas. “Spike!” she called out, tossing a few his way. “Here, eat these!”

“What is it with you two and bananas?” yelled Spike.

“Did you see any brown hoof polish in the throne room?” asked Twilight.

“Yeah, I cleaned it up.”

“Turns out it's poisoned,” said Twilight, taking another bite of banana. “Bananas are the antidote.”

Spike stared at Twilight for a long moment, then rolled his eyes, sighed, and accepted a banana from Pinkie. “Why couldn't you have told me that in the first place?” he asked.

“I didn't know,” admitted Pinkie. “Maybe I should get some bananas, too. Maybe I should declare free banana day in Ponyville, just in case somepony gets poisoned! Maybe every day should be free banana day!” Pinkie drew in a deep breath, and then vanished through the doorway fast enough to leave a Pinkie-shaped dust cloud in her wake.

For a few minutes, the only sound in the room was the sound of an alicorn and her dragon assistant busily chewing their way through the better part of a large bunch of bananas.

Spike was the first to speak. “So, um, who tried to poison you?” he asked.

“Time Turner,” said Twilight. “Only... not Time Turner from now. Time Turner from the future. Time Turner from now identified the poison. And I think Pinkie saved my life with bananas.”

“Huh,” said Spike. “That's... really odd.”

Twilight nodded.

There was a sound of galloping hooves outside, rapidly presenting itself as an out-of-breath brown stallion.

“Time Turner,” said Spike, stepping forward aggressively and folding his arms.

“Not – uh – quite,” he puffed. “Sorry, little – out of – shape.”

“Not Time Turner?” asked Spike. “So are you a spy?”

The stallion shook his head.

“Well, I'm watching you,” said Spike. “You're not laying one hoof on Twi without going through me!”

“Not – planning on – harming her,” panted the stallion. He closed his eyes and took a deep breath. “I should introduce myself. Hello, Princess Twilight Sparkle, Spike the dragon. I'm the Doctor.”

Spike frowned. “Doctor who?” he asked.

“Yes, precisely. One question, Princess. That time traveller who appeared here – how sure are you that he was me?”

“He certainly looked like you,” said Twilight. “I mean, I guess he could have been a changeling... actually, changelings can use magic, so one could have cast the time spell, in theory at least...”

“Hmmm. Okay.” He glanced down at the belligerent little dragon standing firmly between him and Twilight. “One more question then. Do you have any idea why he tried to kill you?”

“No!” insisted Twilight.

“No unsavoury habits?” asked the Doctor. “No hidden desires to kill millions and plunge the world into civil war or anything of that sort?”

“No!” said Twilight, again.

“Who might want to kill you?” asked the Doctor.

Twilight shrugged. “Any villain wanting to take over Equestria, I guess,” she ventured. “Tirek, perhaps.”

“Hmmm.”

“If you're not Time Turner,” asked Spike, “then how come do you look like him?”

“Ah, now there's a story,” said the Doctor. “The short version is, I'm a time traveller from – well, it doesn't matter, it doesn't exist anymore, and now it never did. I arrived on Equestria about... oh... seven years ago? Something like that. My TARDIS – my time machine – was damaged, and to make it worse, I was immediately attacked. Don't know who by. Forced to make an emergency landing. TARDIS badly damaged, not going anywhere. So I hid. Changed myself. Put most of my memories – and some other stuff – inside a brass watch. Forgot it all, until I opened the watch, five minutes ago.”

The Doctor paused for a moment, taking another deep breath.

“Time Turner is, in many ways, who I strive to be. In other ways, he's a... reduced... version of me. There's a lot he, well, didn't remember. He was the perfect disguise – the perfect way to hide from whoever, or whatever, was attacking me.” The Doctor straightened up. “I'm not a killer, Princess. Not if I don't have to be. But if your visitor had been using the time travel spell you're familiar with, the basilisk venom and the hoof polish would have gone back to the future with him. I know how to change it to leave something like that behind... I don't think anypony else would. It really, honestly seems like the future me is trying to kill you. And I, really, absolutely cannot see any possible reason why.” The Doctor smiled, and held out one hoof. “But, after several years in a high-magic harmonic field, my TARDIS will have finished repairing itself. I can't see any possible reason why future me would try to kill you... but would you like to come along and find out?”

“Hold it, buster,” growled Spike. “You're not taking Twilight anyplace without me, got it?”

* * *

“It's an outhouse,” said Twilight.

“It's my TARDIS,” insisted the Doctor.

“It's a bright blue, locked outhouse,” said Spike. “It's been here years, and it's always locked.”

“It's a fully-functional time machine,” insisted the Doctor. “And it's disguised as a police call box, thank you very much.”

“A what?” asked Spike.

“Look,” said the Doctor, pushing the door open and stepping through it, “if you'll just come inside...”

“There's not going to be space for more than one pony at a time!” insisted Twilight. “It's an outhouse!”

The Doctor leaned out of the TARDIS, holding the door open. He raised his eyebrows.

“...it's bigger on the inside?” said Spike, staring at the vista so revealed.

“Yes,” said the Doctor, firmly. “Yes, it is. There is plenty of room for one more pony and a dragon.” He stepped back, into the TARDIS. “Now, if you'll just step along, we can follow this assassin and try to work out what's going on here...”

Shining Armour

“Just how big is this thing?” asked Twilight.

“The TARDIS?” asked the Doctor. “Big enough.” He pulled a lever with his mouth, and then added “It's got a swimming pool.”

“An outhouse with a swimming pool?”asked Spike. He shuddered.

The Doctor turned and glared at the little dragon. “It's not an outhouse.”

“Right. Well. Um. Talking about outhouses, I kinda need to go...”

Twilight frowned. “You should have gone before we left!” she insisted.

“We were going to an outhouse!” insisted Spike.

The Doctor glared at him again.

“To what I thought was an outhouse,” clarified Spike. “You don't go before you go to an outhouse, that would just be silly!”

The Doctor rolled his eyes. “Through that door,” he said, pointing with one hoof, “second door on the right. Not the second door on the left, that's the swimming pool.”

“Right!” said Spike, hurrying in the indicated direction.

The Doctor turned back to the control panel and started fiddling with the levers and switches again.

Several moments passed in silence, then Twilight asked “Do you, um. Do you have any idea why a future you might try to kill me?”

The Doctor nodded. “Yes,” he said.

Twilight stared at his for along moment.

The Doctor sighed, and left the control panel alone for the moment. “Imagine that there's a train,” he said. “It's rushing down the tracks, out of control. Far too heavy to stop. Someone has tied ten ponies to the track in front of the train; you can see that the train will ride over them. Now, you can't stop the train, but there's a lever right next to you that will divert the train onto another track.” The Doctor held up a hoof to forestall Twilight's comment. “Tied to the other track is one pony. Assume that all eleven ponies are complete strangers to you – you don't know who they are what they do, or anything. Would you pull the lever?”

“Um,” said Twilight. “I, um, I would probably cast an intangibility spell on the train...”

“Let's assume you've lost your magic,” said the Doctor.

“Um. Well. Um. I... I guess I would.”

“That would involve killing the one pony,” pointed out the Doctor.

“Yes, but it saves the lives of the other ten,” replied Twilight. “That's... well, that's nine better.”

The Doctor nodded. “I quite agree,” he said. “And that's why future me might want to kill you; to try to save more lives.”

Twilight frowned as she thought about that. “But...if something I was going to do was going to lead to ten ponies dying, and I knew about it, then I wouldn't do it. How would killing me save anypony?”

“I haven't the faintest idea,” admitted the Doctor. He turned back to the TARDIS control column. “Let's go find out. Hah! Strong trace... yes! I've found him! He's not even trying to hide his tracks.”

“You can hide your tracks time travelling?” asked Twilight.

“Oh yes. Dozens of ways. Let's see... he's going further back in time... um... how old are you?”

* * *

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

The sound echoed through the streets of Canterlot. It wasn't loud, as such, but an alicorn's ears are sensitive indeed; and the TARDIS faded into existence mere metres from the outside wall of Canterlot Castle.

Princess Celestia's ears twitched.

She smiled at the trio of ponies standing in front of her. “Mr. Shimmer, Mrs. Glass,” she said, “My school would be most glad to accept your daughter Sunset as a student – assuming, of course, that she passes the standard entrance exam.”

“Oh, she will, your highness,” said Looking Glass, with all the pride that only a mother can show.

“And in light of your financial situation, I will be happy to reduce the usual fee,” added Celestia. “Please talk to Pencil Pusher to get the necessary paperwork. Now, if you will excuse me, an urgent matter has just come to my attention. Steel Shield!”

Steel Shield, captain of the Royal Guard, snapped to attention, his armour jingling. “Yes, your highness?”

“Mobilise the entire guard. Double patrols, medium alert. There may be something... strange... around.”

Steel Shield looked confused; Looking Glass looked surprised.

“Strange how, your highness?” asked Steel Shield.

“I don't know, but if it's dangerous, we'll have help. I just heard an old friend arriving.” Celestia smiled, sadly. “He has a bad habit of turning up just in time to help defeat some ancient evil, and then vanishing again.”

Captain Steel Shield looked nervous. “Very well, your highness,” he said, and marched out to prepare the Guard.

* * *

“Canterlot,” said Twilight, following the Doctor out of the TARDIS. “We're in the Royal Gardens. I... I know this place.”

“Yeah, we both practically grew up here,” added Spike, sitting on Twilight's back.

“Excellent,” said the Doctor. “Now the question is, the important question is, can you remember exactly where you were on this particular day and at this particular time?”

“I was in nappies,” objected Twilight. “And I don't even know what day this is, in any case. Huh, that elm looks a lot smaller than I remember... I don't remember that stinkwood, that's where Celestia's picnic table was...”

“Will be,” corrected the Doctor. “Where Celestia's picnic table will be.”

“Um. Right.”

“Does anypony else smell something burning?” asked Spike.

* * *

The little baby purple unicorn gurgled and laughed at the pretty colours.

She was safe. She knew she was safe, because she was with Big Brother. Big Brother was a white colt who could always chase away any monsters hiding under the bed.

And she was doubly safe, because Big Brother's horn was glowing, sustaining a large, pink shield bubble around them.

Nothing could get through Big Brother's shield bubble, so the flames on the other side were just pretty colours to laugh at.

The flames stopped for a moment, as the grey stallion outside lowered his flamethrower.

“So, very noble and all, Shining Armour, was it?” said the stallion. “But ultimately useless. Consider – your shield either lets air in, or is doesn't. If it doesn't, you'll asphyxiate in there. And if it does...”

The stallion raised his flamethrower again.

“...then the superheated air you're letting in will eventually cook both of you.”

The stallion pulled on the trigger, and there were more pretty colours.

Twilight giggled. “Big Bwuvver!” she said.

Then the stallion spun round, throwing his flame in the direction of two ponies and a dragon, who had been rushing towards him from behind.

* * *

When the stallion turned his flamethrower on them, Twilight Sparkle had only a moment to react. She wrapped her magic around herself and the Doctor, and teleported off to the side. Then she put up her own shield in front of the two of them.

As Twilight vanished underneath him, Spike hit the ground, rolled, and charged.

“Where's the little guy?” asked the Doctor, trying to put out a fire in his mane.

“He's a dragon,” said Twilight, conjuring up a small raincloud over the Doctor. “He's fireproof.”

Spike, meanwhile, had reached the future Doctor; he took a deep breath, and fired a small wisp of flame of his own. It didn't do much beyond causing the stallion to take a few steps back, away from Shining Armour's shield; but that was all Twilight needed. Her horn glowed, as she put up a shield bubble of her own... around the future Doctor. A cooling charm dealt with the superheated air around Shining Armour's shield.

“And do you have any idea why the future me is all grey and faded?” asked the Doctor.

“I think,” said Twilight grimly, “that we are going to have to have a word with Discord about this.”

She took a good look over the trapped stallion. Aside from the grey colouration, the flamethrower, and the faded brown of his mane that suggested dye, the stallion looked exactly as he had when he's appeared in her castle; he still had a strange device wrapped around his forelimb, with a small screen and keyboard.

Twilight glanced aside. Spike was peering into Shining Armour's shield. “Hey, Twily!” he said.

The baby purple unicorn hid away behind her Big Brother's forelegs.

“Who are you people?” asked Shining Armour, staring at them “You!” he added, pointing at Twilight. “Are you Nightmare Moon?”

“What?” asked Twilight, shocked. “No! What gave you that idea?”

“You're not Princess Celestia, and there's not that many alicorns,” said Shining Armour. “And you're purple. That's close enough to dark blue.”

“Will you lot SHUT UP!” yelled the discorded Doctor. “I came here to kill you, not listen to you whine!”

“And perhaps you would like to explain to us all,” asked Princess Celestia, gliding to a stop above the group, “exactly why you decided to do that?” She nodded at the other time travellers. “Twilight, Doctor. Good to see you two again.”

“I don't have to explain a thing to you,” snarled the discorded Doctor. He pointed at Twilight. “You know what you did to me, where you trapped me! But I am Paradox! I am invulnerable, I am unstoppable I am ageless!”

The Doctor's eyes widened. “You didn't,” he gasped.

“I did!” cried Paradox. “I fed all the energy of my future regenerations into my biological matrix! I can't be killed, I can't be wounded -”

“You can't learn,” pointed out the Doctor. “You can't grow. You cannot, ever, change.”

“I know!” said Paradox. “Isn't it brilliant?” He gave the Doctor a mad grin. “And the best of all is, you can't avoid becoming me!”

He reached out a hoof, tapped a few buttons on the device wrapped around his foreleg, and vanished.

There was a moment of silence. The Doctor was the first to break it.

“He's... he's gone,” he said.

“Where to?” asked Celestia.

“Future... past... I don't know.” The Doctor waved his hooves about. “That device he had – it's not really all that accurate. He probably can't get closer than a month or two to when he wants.”

Celestia turned to smile at Shining Armour. “Young colt,” she said, “the danger has passed. You can lower your shield.”

Shining's shield vanished, and he looked up at Celestia in awe.

“Might I ask your name?” she said.

“Oh, um, Shining Armour, your Highness.” Shining suddenly remembered to bow. “And this is my little sister. Twilight Sparkle.”

“Indeed?” Princess Celestia raised an eyebrow, and glanced for a moment at the purple alicorn at her side. “Then these next few decades promise to be quite interesting.”

“Princess?” asked Shining Armour.

“Don't worry about it,” said Celestia. “Did you notice you've got your cutie mark?”

Shining Armour turned to look at his own rear, and his eyes widened.

Celestia

It was about half an hour later; Celestia's guards had returned Shining Armour and baby Twilight to their parents (who had been waiting in the queue of petitioners at the palace) – the last they'd heard was Shining Armour trying to tell his mother that they'd been attacked by “a stallion with some sort of fire wand” and rescued by Nightmare Moon and Princess Celestia working together. It was clear that Twilight Velvet didn't believe a word of it.

Celestia herself, in the meantime, had temporarily closed the day court (citing 'urgent business') and locked herself into a meeting room with her time-travelling guests.

“Are you alright?” she asked Twilight, once she was sure they wouldn't be interrupted.

“I'm fine,” said Twilight. “Why do you ask?”

“The fur on your face is... somewhat singed,” pointed out Celestia. “It doesn't look serious, but I imagine your eyebrows will take a few days to grow back.”

“...huh,” said Twilight. “I must have been a moment too late with that shield.”

“You know us, Princess,” stated the Doctor, bluntly. “You've met us before.”

“Yes,” said Celestia, “I have.”

“Be careful,” said the Doctor, “telling us about it. Whatever it was, it... well, we haven't been there, yet, so -”

Celestia held up a hoof. “I am aware of the risks, Doctor,” she said. “The first time you and I met – from my point of view – you gave me quite a long talk on the subject.”

“Ah,” said the Doctor. “Very well, then.”

Celestia raised her teacup, and took a sip. “I am... very nearly immortal, Doctor,” she said. “My age is best measured in millenia; and you have popped up several times in those years, and dealt – or helped to deal – with a surprising number of threats over the years.”

The Doctor sighed. “I guess that means I'm going to have a busy time ahead of me,” he said.

“So... you've met us before... but we haven't met you before yet?” asked Twilight.

“In the time of my greatest despair,” sighed Celestia. “You came and offered comfort.”

“Ah,” said Twilight. “But... you've never seen Paradox before?”

Celestia shook her head. “Neither seen nor heard of,” she says. “He seems to be interested in killing you, specifically, Twilight?”

Twilight nodded. “Yes, and I have no idea why.”

“Then I shall keep a very close eye on your... younger incarnation,” said Celestia, promptly. “If Paradox should turn up again before you are able to defend yourself, I will make sure that his attempt fails.”

Twilight sat still for a moment, then stepped forward and hugged the larger alicorn. “Thank you, Princess,” she said.

“It is my duty,” said Celestia, with a slight smile of her own. “After all, your younger incarnation is one of my subjects.”

“Right, now that's arranged,” said the Doctor, “and thank you very much, your Highness, but you know things from our future and we know things from your future, so we really shouldn't hang around and chat for too long, spoilers are a serious problem, after all...”

“Do you know where you are going next?” asked Celestia.

The Doctor stared at her. “Um,” he said.

Celestia smiled slightly. “You are welcome to use this meeting room as long as you would like to decide on your next course of action,” she said. “Or you're welcome to adjourn to the TARDIS, if you prefer.” She paused for a moment, before asking “One more question, Doctor. Is it inevitable that you become that – Paradox?”

“No,” said the Doctor, promptly. “It is not.”

“Very well, then,” said Celestia, standing up. “I have a long queue of petitioners to talk to today, so I shall take my leave. I don't know what could happen to turn you into Paradox, but I do urge to try to avoid it as much as possible, whatever it is.”

Celestia stood up, and turned towards the door.

“Princess!” Twilight jumped up. “Did you – you don't recognise what happened to Paradox?”

Celestia turned back slightly, raising an eyebrow. “He turned grey and went homicidal,” she said. “I've never seen that combination of symptoms in my life. Should I have?”

“Um,” said Twilight. “Maybe... maybe not. It, um, it hasn't happened yet...”

“Then don't tell her about it!” snapped the Doctor. “Spoilers!”

“Um,” said Twilight.

Celestia smiled. “I shall leave you to it,” she said. “Besides, Twilight, I still have to listen to your parent's petition.” She stepped out of the room.

“Never?” asked Twilight, quietly. “But that means...”

“Whatever it means,” said the Doctor, “it's better if we don't discuss it here. For one thing, I don't know who else might be listening -”

“I'm sure -” Twilight began.

“For another,” said the Doctor, “the sooner we're back in the TARDIS the sooner I can try to see if I can trace Paradox's next jump.”

“Oh. Right,” said Twilight. A purple glow gathered around her horn; there was a *pop* and a flash of violet light, and both ponies vanished.

* * *

“It would hardly be very secure if anypony could just teleport in,” said the Doctor, opening the door to the TARDIS.

“I guess not,” said Twilight. “Still, I hope we didn't give those foals too much of a fright.”

“They did seem to think that you were Nightmare Moon come to gobble them up,” pointed out the Doctor.

Twilight winced.

“But I'm sure they'll grow up to be fine, well-adjusted adults,” continued the Doctor, reassuringly, as they stepped inside.

“I, um. I think the blue one may have been Trixie,” said Twilight, nervously.

“Who?” asked the Doctor.

“You remember the Alicorn Amulet?” asked Twilight.

“Oh,” said the Doctor, closing the door behind them. “Right. Well, I'm sure that this little incident had very little to do with that. I mean, what'll she tell everypony? That Nightmare Moon turned up and tried to eat her but ran away when she screamed?” He shrugged. “Nopony would believe her.”

“Just like nopony would believe her if she claimed to have defeated an Ursa Major,” mused Twilight. She winced again.

“That might actually be more believable than chasing away Nightmare Moon,” pointed out the Doctor. “I mean, she could potentially meet an Ursa Major, and anypony can occasionally be really, really lucky. But Nightmare Moon is still trapped in the moon, and everypony can see that.”

“...I feel terrible,” said Twilight.

The Doctor rolled his eyes. “Look, Twilight,” he said. “Whatever Trixie says, or does, or will say, or will do in the rest of her life – it's not your fault. It's not your responsibility. She has free will. She has choice. She can choose her own actions, and she – and she alone – has to bear the responsibility for those actions. Nothing that she's done – or is going to do – is your fault, Twilight. Now. You seemed to indicate earlier that you knew what had happened to Paradox, to make him so, well -” The Doctor waved a hoof.

Twilight nodded. “Yes,” she said. “Discord did the same thing to my friends, the first time we met him; he turned them grey, and made them act the opposite of themselves. I found a way to reverse it, by reminding them of who they had been before with a memory spell...”

“That won't work on Paradox,” said the Doctor. “He's – as I said – made himself immune to any and all forms of change. Injury, age, experience – even a cure. He... he can't be cured unless he wants to.”

“I don't think that will work, then,” said Twilight. “All of my friends fought back when we tried to cure them. Do you know of any way to stop him?”

“Short of throwing him into a black hole?” asked the Doctor. “I don't think he can be stopped, as such. But it is possible to... limit... how much damage he can do.”

“I'm sure we can dig a hole,” said Twilight, mystified, “but why does the colour matter?”

The Doctor sighed, and waved a hoof. “Just think of it as an inescapable prison,” he said. “A place that nothing leaves from, or can leave from, until it evaporates a few billion years in the future... and then all Paradox would need to do is build a new time machine, and he can turn right up again.”

Twilight nodded, uncertainly.

“No,” said the Doctor. “No, that's really not that good an option. You say it was Discord who did it to your friends?”

Twilight nodded. “And... Celestia said that she'd never seen him do it before... so, if it was a new idea at that time, then that must mean... he wouldn't have had much chance or reason to pick on you the first time he was freed, and the second time Fluttershy kept a very close eye on him until...” Twilight frowned in thought. “Doctor, before we continue following Paradox, do you mind if we make a bit of a detour, back to the future? I think I want to talk with Discord, as soon after Tirek's defeat as you can get us without meeting my past self; we might be able to resolve this entirely by preventing Paradox from ever existing at all...”

Discord

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

Deep in the Appaloosan Desert, a blue police box that was most certainly not an outhouse faded into view. The door opened, and Twilight stepped out, alone.

The door swung shut behind her.

Twilight looked out at the sand, more sand, and a single hardy cactus, growing almost right next to where the TARDIS had landed. There was no sign of anypony for miles around. She took a deep breath. “DISCOOOOOORD!”

“Alright, alright, there's no need to shout, I'm right here,” said the cactus.

Twilight turned and stared as the cactus unfolded mismatched limbs, quickly transforming into a familiar draconequus.

“And might I say,” added Discord, “you're looking particularly sooty today. It's an interesting new look, I'll grant you that, but it just needs a certain je ne sais quoi... no, wait, I do know what.” Discord reached behind his back and pulled out a flower, which he tucked neatly behind Twilight's ear. “There,” he said, conjuring up a mirror so Twilight could see her reflection. “Much better, don't you think?”

Twilight sighed, and closed her eyes. “Thank you, Discord, but my appearance is hardly a major concern at the moment. I do have a few questions, if you don't mind.”

“Oh, not in the least, not in the least,” said Discord. “The first three answers, in order, are of course I do, your diary, and of course, Princess.”

Twilight glared at him.

“Oh, my apologies, should I have waited for you to ask the questions first?” said Discord, grinning widely.

“Do you remember what you did to my friends in the maze, turning them grey and inverting their personalities?” she asked.

Discord smiled. Twilight stared at him.

“Surely I don't need to repeat myself?” asked Discord.

“Where did you get that list of answers from anyway?” asked Twilight.

Discord raised an eyebrow.

“But I don't keep a diary!” objected Twilight.

“You had better start one then, hadn't you?” Discord asked, his smile slowly widening.

Twilight glared at him.

“If you didn't want me to read it,” Discord finally said, “then why did you hide it in a triple-locked lead safe in the basement of Town Hall in a disused lavatory with a sign on the door saying 'Beware of the Leopard'?”

Twilight sighed. “Alright, we'll worry about the diary later,” she said. “Now, could you please not answer my questions before I ask them? It's really confusing.”

Discord grinned. “Of course, Princess,” he said.

“Okay, good.”

“Of course,” continued Discord, “this whole business of time travel is just full of confusion, isn't it? It's a pity I'm immune.”

Twilight blinked. “Immune?” she asked.

“Why, didn't the good Doctor mention it?” asked Discord. “As the amazingly handsome and absolutely perfect avatar of Chaos, I'm a fundamental force of the universe. Fundamental forces of the universe can't travel through time. Why, it's one of the few things that I have in common with your dreadfully tacky Elements of Harmony; if either of us were in that TARDIS and you left, you'd just leave us behind.”

“But, I've time-travelled,” objected Twilight. “And I'm the -”

Discord shook his head. “No, no, no, no, no,” he said, firmly. “You were the Bearer of the Element of Magic. You were never the Element itself. And you gave up even that much when you put your element back on the Tree. You are free to time travel to your hearts' desire, but your pointy little purple gem has to stay behind.” He drifted through the air, looping around to the other side of Twilight. “As one of the few things I can't do, I must say I've always been kind of fascinated by time travel,” he continued. “Did you know, I once tried to make a collection of Time Travellers? Before my reformation, of course. But why don't you introduce me to this Doctor of yours?”

“Oh! Right.” Twilight shook her head. “Before we do that, Discord, I want to ask you to promise me something.”

“Ohhhhhh,” said Discord. “I'd almost forgotten about that. Didn't you have some other questions first?” He raised an eyebrow. “Your diary was quite detailed about what you'd planned for this meeting, you know.”

Twilight nodded. “You turned my friends grey,” she said. “Have you ever – ever – done that to anypony else?”

“Of course not,” snorted Discord. “Chaos is all about not repeating yourself. Doing new stuff, not old stuff.”

“Okay, then,” said Twilight. “Could I ask you to Pinkie Promise not to do that to anypony at all for, say, the next hour?”

Discord shrugged. “Sure,” he said. “Cross my heart, hope to fly, stick a cupcake in my eye.”

There was a squelch as the cupcake, appearing out of nowhere in his eagle claw, hit him in the eye. Twilight winced, but Discord didn't appear to be in any discomfort. She reached out one rear hoof and knocked on the TARDIS door.

It swung open, and the Doctor stepped out.

“Doctor,” said Twilight, introducing the two, “Discord. Discord, the Doctor.”

“Doctor who?” asked Discord, reclining back on the air.

“You were talking about the Doctor earlier,” said Twilight, ignoring Discord's question. “You've met him before?”

“Oh, yes,” said Discord. “Reasonable fellow. Bit gruff. No sense of humour, but he's done some amazing things. Really, amazing.”

“Have you ever met sompony who looks like him, only grey?”

“You mean Paradox?” asked Discord. “Oh, yes.” Discord shuddered. “Horrible fellow. Absolutely terrible.”

“Right, well -”

“Oh, now, wait a minute!” said Discord, suddenly sitting up. “You don't honestly think I turned the Doctor into that – that thing, do you?”

“Well, not yet, perhaps,” said Twilight. “But he is a time traveller, so -”

Discord snapped his talon. The Doctor gasped, and backed up a few steps.

“I hereby Pinkie Promise,” said Discord firmly, “that I have not and never will invert the Doctor's personality. Cross my heart, hope to fly, stick a cupcake in my eye.” This time, the cupcake squelched into his other eye, leaving both covered.

Discord snapped his talon again.

“There,” he said. “That should resolve that, at least.”

“You can't do that!” objected the Doctor.

“I just did,” grinned Discord. His eyes opened on the outside of the two cupcakes.

“What?” asked Twilight. “He promised never to invert you! Isn't that a good thing?”

“Not that!” said the Doctor. “I mean, yes, that is a good thing, but, he just created a fixed point in time!”

Twilight looked back and forth between the Doctor and Discord. “A what?” she asked.

“Oh, come now.” said Discord. “It's a perfectly sensible thing to do. If I didn't, then some grey-coated time traveller could try to change history to prevent me from ever making that promise, couldn't he? I made it, and I intend to keep it.” He leaned closer to whisper to the Doctor. “Paradox is a lot less fun than you are, anyway.”

“What's a fixed point in time?” asked Twilight.

“It's an event that has to happen,” explained the Doctor. “Something that you can't prevent without breaking time itself.”

“And in this case,” continued Discord, “the fixed point was me, having been reformed, making a particular Pinkie promise truthfully and with every intention of keeping it.”

“And you can't just create one of those!” continued the Doctor. “Not so quickly, at least!”

“I thought you said you were immune to time travel,” said Twilight.

“Oh, and I am!” insisted Discord. “But I didn't exactly travel through time to do that, did I?”

Twilight sighed. “Sometimes I think Discord does impossible things just to mess with people,” she told the Doctor.

“You said you'd met Paradox before?” asked the Doctor.

“Oh, yes,” said Discord. “About, oh, two hundred miles south of Baltimare, one thousand, three hundred years ago? More or less, I never really bothered to keep accurate dates at the time. It was before I was reformed, you see, so I had no reason to keep track of whether or not it was Tuesday.”

“What do Tuesdays have to do with -” began the Doctor.

“Oh, and talking of which,” said Discord, “it just happens to be a Tuesday today. Time for my weekly lunch with Fluttershy. Toodles!”

He snapped his talon, and vanished.

There was a long moment of silence. Twilight broke it first.

“Do you think that will be enough to stop Paradox?” she asked.

“Will he keep that promise?” asked the Doctor.

“I do believe he would,” said Twilight. “It was a Pinkie promise, after all.”

“In that case,” said the Doctor, “no, it won't be enough to stop Paradox.”

“But -” began Twilight.

“The only reason you're here, now, is because you met him,” pointed out the Doctor. “Remove him from history, and you've got no reason to ask Discord to make his fixed-point-in-time promise. And time can't let that happen.” He shook his head. “No,” he said, “it is now completely impossible to prevent Paradox from ever having existed at all. We're just going to have to track him down again, and... and figure something out.”

“Could you find out where he went when he left Canterlot?” asked Twilight.

The Doctor shook his head. “No,” he said. “That jump has too much interference. Paradox is hiding his tracks.”

“Then how can we find him?” asked Twilight.

“Well,” said the Doctor, “I do have one clue. Apparently he was about two hundred miles south of Baltimare, one thousand three hundred years ago...”

dIsCoRd

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

The blue police box fading into view wasn't the strangest sight to be seen, on this plaid field, under the butterscotch sky. A flock of cherry pies flew past as the doorway opened, and the miniature elephants ran and hid under the giant shoes.

“This is not what I expected ancient Equestria to look like,” admitted the Doctor, stepping out onto the rough plaid surface.

“The Reign of Discord,” said Twilight, trotting out behind him. “Given the clue we're foll-”

“Did I just hear somepony call?” asked Discord, appearing right behind them.

The TARDIS door instantly slammed shut.

“And I don't believe I've seen either of you before,” added the draconequus, with a nasty grin. “In fact, I'm quite sure that little miss magical over there -” he nodded at Twilight - “didn't even exist a moment ago. Isn't that interesting?”

“I'm a time traveller,” said Twilight, promptly.

Next to her, the Doctor sighed and facehooved.

Discord raised an eyebrow. He snapped his talon, causing a tall glass of strawberry milk to appear, along with a straw that had more loops and twirls than a drunk Wonderbolt.

“We're actually looking for somepony,” continued Twilight, nervously. “Perhaps you could help us find him?”

Without changing his expression, Discord raised the crazy straw to his mouth and drained the glass. He tossed the empty glass into a passing toffee cloud and then, quite suddenly, spat all of the strawberry milk out again, soaking Twilight.

“Time travellers?” he yelled.

“Yes,” said Twilight, her mane dripping with strawberry milk and her flower drooping. “From the future. We're actually trying to track down another one...”

“Yes,” said Discord, nodding at the Doctor, “I can see the similarity.” He swooped closer, and the Doctor backed away nervously. “Is that a dye job? Are you going grey and trying to hide it?”

“Um, well, no, I -” began the Doctor, but Discord just rolled his eyes.

“Bored now,” he said. “Did you know what the other guy can survive?”

“Practically anything?” asked the Doctor, nervously.

“Are you implying that there might actually be another way to hurt him?” asked Discord. “One that sticks, I mean? You'd be amazed what he can survive. He could probably even live through that 'eternal night' he keeps going on about.” Discord looked up at the horizon. “And what do you know, here he comes now.”

“Another way?” asked the Doctor. “You've actually found a way to -”

There was a distant, but continuous, scream from behind a nearby cream donut hill. A squadron of tap-dancing giraffes clattered by.

“- cause harm to him?”

A spinney of trees ran past, hotly pursued by a beaver with a chainsaw.

“Oh, I'd hardly call it harm,” said Discord, leaning one elbow on the Doctor's head. “It's great, really; your average pony just breaks apart so easily, but he, ah, he is durable.”

The distant scream was getting louder now, accompanied by a quieter sound, as if of somepony singing. A swarm of Peruvian death butterflies went by, pursuing a dog on a pogo-stick.

“It's just a pity he's such a dull and humourless fellow,” continued Discord. “Though I have been trying to figure out the secret to his durability, and if I can provide it to other ponies, then perhaps I won't keep breaking my toys all the time...”

Paradox rounded the cream donut hill while Twilight was staring in horror at Discord. He slammed straight into the Doctor, knocking both timeponies to the ground.

He was being followed by a singing harp.

I know a song that irritates people, irritates people, irritates people
I know a song that irritates people, and this is how it goes!

I know a song that irritates people, irritates people, irritates people
I know a song that irritates people, and this is how it goes!

“I've had Louise following him around for almost ten years now,” grinned Discord.

“How could you?” asked Twilight. “Those are ponies we're talking about, not toys!”

“Eh,” said Discord, waggling his lion paw. “Same thing. It's not like I don't put them together again afterwards. More or less. Sometimes. Hey, watch this!”

Discord reached into nowhere and pulled out a giant hammer. He swung it around, and slammed it directly onto Paradox – or rather, onto the spot where Paradox had been. Paradox leapt aside at the last moment.

Discord frowned, and started producing water balloons from nothing; Twilight wasn't sure what the balloons were filled with, but normal water balloons don't start small fires where they land.

Somehow, Paradox managed to dodge them all, even the ones that turned around and tried to hit him from the rear. Then he ducked, spun, and kicked Discord in a spot that would hurt any male.

Discord's pained screech was green and tasted of apples. He promptly vanished, with a pop.

Paradox growled. “Come to gloat, have you?” he asked.

“Not in the least,” said the Doctor, firmly. “Just trying to find out exactly what you intend to accomplish.”

Paradox snorted. “Gloating,” he said. “I was once you, Doctor. I know what you're thinking. How do you think I dodged the fire balloons? I remembered their trajectories, Doctor, because I've seen them. Through your eyes.”

“No,” said the Doctor, “I don't think that's right.”

Paradox roared in anger, leaping at the Doctor; only to be caught and lifted away by Twilight's telekinesis.

“I'LL KILL YOU!” he screamed. “I'LL HIT YOUR TARDIS WHEN IT FIRST ARRIVES, DAMAGED AND LIMPING – I'LL KILL YOU, TWILIGHT, BEFORE YOU KNOW TO AVOID ME – I'LL SHROUD THE ENTIRE PLANET IN ETERNAL NIGHT AND DESTROY EVERYTHING AND EVERYONE YOU'VE EVER KNOWN!”

“Annnnnnd that's that,” said the Doctor, heading back to the TARDIS. “Come on, Twilight, we should get going before Discord gets back and tries to add us to his 'collection' of time travellers. I know when to go next, now.”

“Coming,” said Twilight.

Paradox apparently found something funny; he burst into crazed laughter as Twilight carefully moved him far enough away that he couldn't rush the TARDIS while the door was opened.

* * *

The moment Twilight stepped into the TARDIS, the flower in her hair wriggled and bent. And there was another movement in her mane as well.

Twilight stopped walking, the door clicking shut behind her. “Um...” she said, nervously.

And then the strawberry milk that still soaked her mane shifted, reaching out one long, strawberry pseudopod in the direction of the TARDIS control column...

...but even as it did so, Twilight's flower slurped it down, drinking the strawberry milk and developing a rather large bulge on the lower end.

“...what just happened?” she asked.

“I'm... not sure,” admitted the Doctor. He pulled on a lever, and the TARDIS slipped out of normal time. “How much do you trust future Discord?”

Twilight considered the question for a few moments before replying. “I... trust that he wouldn't permanently harm me,” she said after a bit.

“Then you're probably safe,” said the Doctor. “Whatever the strawberry milk from the younger Discord was going to do, the flower from the future, reformed Discord prevented it. Have I shown you the chameleon arch yet?”

“What? No, but...” Twilight trotted hurriedly towards the Doctor.

“Perfect time to show you,” said the Doctor, hurrying deeper into the TARDIS. “I think I know what's going on with Paradox, and it's... really not pleasant... but I need to make sure.”

“Doctor, when are we going to?” asked Twilight.

“Isn't it obvious?” said the Doctor. “We're going to the thousandth Summer Sun celebration.”

“...eternal night,” said Twilight. “And it's probably the only time in my life when Celestia wasn't there to protect me.”

The Cutie Mark Crusaders

“First things first,” said the Doctor, opening a door deep in the TARDIS. “This is the chameleon arch. It's the device that changed me – temporarily – into Time Turner, leaving my memories, and any other differences between me and an ordinary earth pony, trapped in a brass watch.”

“Are you going to do that again?” asked Twilight.

“No, no, no,” said the Doctor. “No point. No, I'm going to change the settings quite a bit.” He tapped on a control panel, turning several dials far to the left and flipping a few switches, causing several little lights to turn off.

“Um, so... what exactly are you, um...”

“Doing?” said the Doctor. He gave Twilight a brief smile. “I'll tell you in a minute. Just wait out here for a moment, will you?”

“Um -” said Twilight.

“Excellent,” said the Doctor, stepping forward under the arch and hitting a button. The arch flashed, just once, and the Doctor winced; then there was a rattling somewhere inside the machinery, and a brass watch popped out of a panel.

“Was that it?” asked Twilight.

The Doctor nodded. “Oh, yes,” he said. “Much quicker and less painful than using the full features of the arch.”

“So... what exactly did you just do?” asked Twilight.

“Glad you asked,” said the Doctor. He reached out and grabbed the watch with one hoof. “This watch,” he continued, “now contains the only copy of my memories of Paradox dodging... er... whatever it was Discord was throwing at him. Come along, I need to test something.”

The Doctor rushed past Twilight, further down the corridor, until he reached another room; this one had a small alcove in the wall, into which he tossed the watch.

“And... where does that go?” asked Twilight.

“Garbage disposal,” said the Doctor. “It'll get broken apart by the TARDIS' internal systems. Smashed to pieces. Destroyed. Obliterated. I can't get it back now, even if I wanted to.”

Twilight frowned. “Why would you destroy part of your own memory?” she asked.

“Let me ask you a question,” said the Doctor. “When Discord was throwing things at Paradox, did he dodge them all? As if he knew where they were coming from, and remembered their trajectories?”

“Er, yes,” said Twilight. “Yes, he did. He said it was because he remembered them – because he'd seen their trajectories, through your eyes.”

“He remembered them, yes,” said the Doctor, looking down at the garbage disposal. “But he didn't get those memories from being me. Because he wasn't ever me.”

Twilight frowned. “So... he's a future Discord?”

The Doctor shook his head. “Discord can't time travel,” he said. “Paradox can.”

“But – that only leaves me!” said Twilight. “Paradox must be a future me!”

“I doubt that, very, very much,” said the Doctor. “You don't have future regenerations to redirect into your biological matrix.”

“But,” said Twilight, “who else was there to see the balloons? ...do you think he could have been the beaver with the chainsaw?”

* * *

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

The TARDIS faded into view in the middle of Ponyville Town Hall. The door opened, and the Doctor stepped out. He glanced around – tables overturned, decorations ruined, but the Town Hall itself was empty, panicking ponies having already fled. And outside, an unmarred white moon hung in the sky.

Importantly, there was no sign of the younger Twilight. But, just as the Doctor turned aside to call the older Twilight, a voice cried out to him.

“Doctor!” said a small orange pegasus filly. “There you are!”

“We're at th' wrong Summer Sun Celebration!” added a yellow earth pony. “We got th' year of Nightmare Moon's return!”

The Doctor frowned at them. “Do I... do I know you?” he asked.

“Aaaaaah!” screeched the small white unicorn. “We changed history! Now it's all messed up! We've probably never been born or something!”

“We can't've done that!” objected the earth pony. “We never went back t' before we were born!”

“Applebloom?” asked Twilight, only her head poking around the door of the TARDIS.

“Princess Twilight!” called out all three Cutie Mark Crusaders, in the fearful tones of a small child suddenly meeting an unexpected authority figure.

It was at this point that a throat was cleared near the front door of Town Hall. The Doctor was standing there.

Twilight and the Crusaders both immediately turned their heads to look back at the Doctor still standing in front of the TARDIS. Then they all turned back to look at the Doctor standing by the door.

Two Doctors.

“Terribly sorry about all this,” said the Doctor by the door. “Teeny little problem targeting the right year. Crusaders!” He stomped one hoof. “You're with me, my TARDIS is parked round the back, right where it was when you stepped out of it.”

“You mean we didn't mess up time so we were never born?” asked Sweetie Belle, hopefully.

“No, you didn't,” said the Doctor by the door.

“You took the Cutie Mark Crusaders time travelling?” asked Twilight. “The... Cutie Mark Crusaders?”

The Doctor by the door shrugged. “It seemed like a good idea at the time,” he explained. “Oh, and by the way, you've got the wrong end of history. Paradox didn't pick this appearance of Nightmare Moon.”

“What?” asked Twilight.

“Can't say any more,” said the Doctor by the door. “Spoilers. Come on, Crusaders, let's go!”

“Cutie mark crusader time travellers, yay!” chorused the Crusaders, as they trotted out after the Doctor.

Twilight gave the Doctor a plaintive look. “Surely you're not going to take the Cutie Mark Crusaders time travelling?” she asked.

“It seems likely that I will, at some point,” said the Doctor, drily. “Come on, it looks like we should be going to the original appearance of Nightmare Moon, instead.”

“Right. Um. Can we stop somewhere else first?”

The Doctor rolled his eyes. “What exactly do you have in mind?” he asked.

“Well,” said Twilight, “just before the first time I met you, Pinkie said something about just having seen me, with a flower in my mane and my eyebrows scorched, and I'd told her to feed me bananas. And since I currently have a flower in my mane and scorched eyebrows...”

“So you want to close that loop,” said the Doctor. “Well, fair enough, I guess.”

* * *

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

The TARDIS faded into view in an alleyway in Ponyville. Both the Doctor and Twilight stepped cautiously out.

“Alright,” said the Doctor, “so where's your friend usually at this time of day?”

“Kind of hard to predict,” said Twilight. “But... you're not the same person as Time Turner, right?”

“We... share a lot of similarities,” said the Doctor.

“And, so while you may have passed through Ponyville before, you've never really stayed here?”

“...yes?” said the Doctor, cautiously.

“So that means you're new in town?” asked Twilight.

“Technically,” said the Doctor, “but why -”

“Oh wow you're new did you know you look just like Time Turner he lives just down the road over that way he fixes clocks what's your name?” asked a pink mare, suddenly bouncing along on the other side of the Doctor.

“And that's how you find Pinkie,” said Twilight, grinning.

“Ooooh, is he a friend of yours?” asked Pinkie. “Why were you looking for me? Are we playing hide and seek? I love hide and seek! Oooh, have you got a joke flower in your mane?”

“No, Pinkie,” said Twilight. “I need you to do something very, very important for me.”

“Sure!” said Pinkie. “A party for your new friend?”

“No,” said Twilight, “even more important.”

“Wow!” said Pinkie. “It must be really important if it's more important than a party!”

“I want you to go to the market,” said Twilight.

“Market,” said Pinkie, nodding.

“And get a big bunch of bananas,” continued Twilight.

“Bananas!” said Pinkie. “Got it!”

“And then,” said Twilight, “I want you to go to the Friendship Castle, where you'll meet me.”

“Meet you at the castle,” nodded Pinkie.

“And then I want you to feed me the bananas,” said Twilight.

“Feed you the bananas,” said Pinkie.

“They're a good source of potassium,” explained the Doctor.

“Okie dokie lokie!” said Pinkie, bouncing in place. “Anything else?”

“Hmmm... afterwards, you'll need to go inside the castle and give Spike some bananas as well,” said Twilight.

“Is potassium good for dragons?” asked Pinkie.

“Right now, he needs lots of it,” said Twilight, firmly.

“Okay!” said Pinkie, saluting. “Pinkie's on the job!”

She charged away at full speed, in the direction of the market.

There was a brief silence. Then the Doctor asked, “Anything else you need to do while we're here?”

Twilight considered it, then shook her head. “No,” she said. “No, I don't think so.”

“Right,” said the Doctor, leading the way back to the TARDIS. “Well, then. Next stop, Nightmare Moon.”

The Nightmare Confrontation

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

The door to the TARDIS opened, and Twilight and the Doctor cautiously peered out. They both glanced first at the moon; pristine and white.

“Well, Luna hasn't been banished yet,” said Twilight. “We seem to be right on time.”

“Of course,” said the Doctor. “Now, how can Paradox prevent Nightmare Moon's defeat?”

“The easiest way is probably to somehow sabotage the Elements of Harmony,” said Twilight. “Celestia was reluctant to fight against her sister, while Nightmare Moon was more than willing to injure Celestia; without the Elements, I'm not sure Celestia could have made it.”

“That makes sense,” agreed the Doctor. “Do you know where the Elements are in this time?”

“Under the Castle of the Two Sisters,” Twilight said, promptly. She pointed at a nearby building.

The Doctor nodded. “Then let's go check up on them,” he said. “Does it have tapestries?”

“Yes,” said Twilight. “It's famous for them.”

“Good,” said the Doctor. He cantered along the side of the building, until he reached a door. He knocked, and the door instantly opened.

“Tapestry inspector,” said the Doctor, not paying attention to the pony who had opened the door, “come to inspect your – oh.”

Paradox grinned at the Doctor. He was wearing a bulging pair of saddlebags.

Twlight, who had been paying attention when Paradox had opened the door, had her wings spread slightly, her head lowered, and her magic ready.

“Well, hello, Doctor,” said Paradox. “I must say, I really thought I'd lost you with that last jump.” He stepped outside the palace, closing the door behind him. “Not that it really matters,” he continued. “You're not going to exist for long. Oh, and do tell your pet alicorn to stand down, would you? There's nothing either of you can do now to save yourselves.”

“I doubt that,” said the Doctor. “I doubt that very much indeed. Let me guess – you've sabotaged the Elements in some way?”

Paradox smirked. “I've stolen Laughter,” he said. “Without one of the Elements, their power is weakened; Celestia will die, and by the time you arrive, Doctor, injured and alone, your TARDIS weakened and damaged, there won't be anypony left alive. Without a safe place to rest and recover, you will die, Doctor. You will die, and then I... I will never have existed.”

Twilight frowned. “You... you want to not exist?” she asked.

Paradox's expression darkened. “Do you know how I escaped from Discord?” he asked. “He never took away my time machine, no. He just activated it, sending me back to the beginning, time and time again. There was no escape through time, Princess. So I did the only thing I could.” Paradox strode forward, forcing Twilight back. “I waited.” said Paradox. “I was his plaything, Princess. I was the toy that never broke. But just because I can't be injured doesn't mean I can't feel pain, Princess. I had to wait him out, Princess, destroy my time machine and rebuild it after his defeat. I had to wait, I don't know how long, it must have been at least three hundred years. And not just once, Princess. Time and time again. And every time, there's only one thing that keeps me sane, Princess. Knowing that when I get out, I am going to make it not have happened. The first thing I do when I get out, Princess, every time – I try to kill you. And this time – I'm going to succeed.”

“No, you're not,” said the Doctor. “I'm... sorry. I really am. But you can't win here. It's temporally impossible. You'd know that... if you were honest with yourself.”

“I'LL KILL YOU!” yelled Paradox, leaping for the Doctor. Before he could reach his target, though, Twilight grabbed him in her magic, and lifted him up and away.

“So we just need to take Laughter out of his saddlebags, and put it back with the other Elements?” asked Twilight. “This should be easy.” The left saddlebag opened, and Twilight pulled out a familiar blue crystal.

...a whole series of familiar, and identical, blue crystals.

Paradox laughed maniacally. “It doesn't matter!” he cried, triumphantly. “There's no way you can tell the real from the fakes in time! Even if you manage to get one in place, it'll never be the right one!”

“Telling a real Element of Harmony from an inert sapphire is a fairly simple spell,” said Twilight. “It only takes a minute or so to cast.”

“And just how many minutes do you think you have?” snarled Paradox.

* * *

“There can only be one Princess in Equestria! And that Princess,” Luna said, stomping her forelegs, and destroying the bridge that symbolically connected her and Celestia's thrones, “will be ME!”

* * *

Twilight looked up as a window in the Castle of the Two Sisters suddenly blew inward. And then she looked further up, as the moon moved directly in front of the sun, and an unnatural night fell over the city.

“...not enough minutes,” she admitted.

A triumphant burst of evil laughter sounded from inside the Castle.

“Look, Paradox,” said the Doctor, “it's still possible to help you. We don't have to fight. You don't have to kill anypony.”

Paradox grinned. “Too late, Doctor,” he said. “I've killed you all already. And if it doesn't stick then I'll do it AGAIN and AGAIN until you're DEAD!”

Twilight shook her head. “No,” she said. “I think I know how to fix this.” She glanced up, as a beam of cyan light sliced out through the roof of the Castle.

Paradox screamed incoherently, legs flailing as he struggled against Twilight's magic. “I'LL KILL YOU!” he yelled. “I'LL KILL YOU I'LLKILLYOUI'LLKILLYOUI'LLKILLYOU! I'LL KILL YOUR PARENTS BEFORE YOU WERE BORN! YOUR GRANDPARENTS! GREAT-GRANDPARENTS! I'LL GO UP AND UP THE FAMILY TREE UNTIL I SUCCEED!”

Twilight calmly put the crystals – all of them – back into Paradox's backpack. And then she pressed one hoof down on the bulge at the bottom of the flower that Discord had given her.

A stream of strawberry milk spat out at Paradox, and immediately grabbed his time machine. The milk hit several buttons, and with an even louder scream of rage, Paradox vanished.

One single blue crystal remained where he had been. From its position, Twilight guessed that Paradox had swallowed it.

“The Elements of Harmony,” said the Doctor, recalling their earlier conversation with Discord. “Can't travel through time.”

“Exactly,” nodded Twilight. “I've got to -”

“Put that back and then get out here so I can yell at you!” said the Doctor. “Do you have any conception of what you just did?”

The Celestia Confrontation

Celestia screamed in pain as a lance of cyan magic struck her from the sky. Her wings failing, she fell like a rock through the hole that Nightmare Moon had left in the castle roof, leaving the dark alicorn to cackle triumphantly over the city.

Though injured, however, Celestia was not defeated. Her earth pony endurance had her back on her hooves mere moments later.

“Oh, dear sister,” she said, her horn glowing yellow. “You have given me no choice but to use – these.”

A panel on the floor glowed and slid aside, and the Elements of Harmony raised themselves into view. Laughter sat in its proper place, a blue crystal, hovering above a stone platform on the upper row.

* * *

Below, in the basement, Twilight sighed with relief. She had been in time. She felt the Elements activate, first protectively around Celestia, and then she felt the wave of magic as they launched a beam of rainbow power against the combined might of Luna, Princess and Monarch of the Night, and the Nightmare in her head.

And then, while that massive font of harmonic energy was present, she teleported back to the castle doorway, where the Doctor was waiting.

“You... said you wanted to yell at me about something?” she asked. “I'm not – quite exactly sure what, but...”

“It's not the right time,” said the Doctor, watching the silhouette of Luna appear on the moon. “Right now, you need to talk to Celestia. I'll yell at you when we're back when you came from.”

“...talk to Celestia?” asked Twilight.

The Doctor rolled his eyes. “Surely you remember,” he said. “Celestia said that in her time of greatest despair, you came and offered comfort, which quite honestly sounds like an absolutely wonderful thing to do. Now, she's just banished her sister to the moon, this is her moment of greatest despair, so you can go in there and offer comfort!”

Twilight squealed and backed off a few steps. Then she turned about and ran back into the castle.

* * *

Celestia was sobbing as she placed the Elements back into storage. She didn't hear, at first, the clip-clop of hooves on the floor.

She did hear the voice. “Princess Celestia?”

“Leave me,” she said, without looking up.

“I, um, I don't think that's...” The voice trailed away.

Celestia looked up, to see who would bother her in her time of grief. She saw a purple pony, saw the horn, saw the wings – and suddenly Celestia was standing up on all four hooves, bacjing away from the stranger, with her wings half-unfurled and her horn glowing yellow. “You will NOT replace her!” she hissed.

“What?” asked the purple alicorn. “No! I wouldn't even try to -”

“Then why are you here?” asked Celestia, not relaxing her threatening stance in the slightest. “Why do you arrive when I've just lost my sister forever?”

“Um. It's... it's not going to be forever,” said the smaller alicorn, nervously.

“Do not give me false hope,” snarled Celestia. “Even if it were possible to return her from the Moon, she would still be homicidal.”

“It, um, it does work out in the end...”

“And HOW could you KNOW that?” screamed Celestia.

“Um. I'm... from the future?” The purple pony gave Celestia a nervous grin. “And I've met Luna, there. She's a, a good friend. And completely non-homocidal.”

The yellow glow around Celestia's horn faded, and she looked up at the other alicorn. “If I find that you are lying to me...”

“I'm not!” squeaked the alicorn, nervously.

“Are you familiar with a blue outhouse?” asked Celestia, sharply.

“It's not an outhouse!” said Twilight, quickly. “It's, alright it looks like an outhouse, but it's what the Doctor calls a TARDIS...”

“...alright,” said Celestia, folding her wings. “Perhaps you really are from the future then, and in all likelihood you will go back there, shortly. In which case I have only one further question to ask. How long?”

Twilight blinked.

“How long until my sister is returned to me?” asked Celestia, sharply.

“Oh! Um. There was this, um, this prophecy I read in a book once...”

Celestia raised an eyebrow.

Twilight cleared her throat and sat straight. “On the longest day of the thousandth year, the stars will aid in her escape, and she will bring about night-time eternal.”

Celestia made a strange squeak. “Night-time eternal?” she asked.

“That part didn't happen!” Twilight said, quickly. “I mean, she tried, but -”

“I think that's quite enough, Twilight Sparkle,” said the Doctor, marching in behind Twilight. “We do not want spoilers, and you have said too much already.”

Celestia's eyes widened slightly. “Twilight Sparkle...” she said, very, very quietly.

“Your sister will be back, Princess,” said Twilight, as she stood up.

“Well done, we've established that,” said the Doctor. “Now, shall we leave before you say something you shouldn't and make this a worse mess than it already is?”

Paradox Explained

Twilight opened the TARDIS door, and stepped inside, just ahead of the Doctor.

She almost ran into Spike, heading out.

“Spike?” she asked. “I thought you were going to stay in the TARDIS?”

Spike crossed his arms. “I was worried,” he said. “You weren't coming back... I was going to look for you.”

Twilight smiled, and nuzzled the little dragon. “Spike,” she said, “you know why you couldn't come with. A dragon – even a baby dragon – in old Everfree City would have caused a massive panic. Ponies could have been hurt. It could have been a disaster.”

“It was a disaster,” said the Doctor, closing the door behind himself. “It's hard to see how Spike could have made things any worse, exactly.”

“I... still don't know what I did wrong, Doctor,” said Twilight, meekly. “I saw a way to get Laughter back without causing any more prob-”

“Do not finish that sentence.” The Doctor pointed a hoof at Twilight. “You didn't need to get Laughter back, and you caused massive problems up and down the timeline!”

Twilight frowned. “I... don't get it.”

“What exactly did you do?” asked Spike.

“I managed to trigger Paradox's time machine,” said Twilight, “sending him back to Discord's time again. Since Laughter couldn't travel through time, it was left behind.” She turned to face the Doctor. “But, Doctor, without Laughter, Celestia wouldn't have the Elements of Harmony. Nightmare Moon could have defeated her, easily.”

The Doctor rolled his eyes. “You're an alicorn, idiot!” he snapped. “Nightmare Moon could perhaps have defeated Celestia, but she could never have defeated the two of you working together!”

He stomped over to the TARDIS' controls and started flicking switches and pulling levers.

“Oh. I... didn't think of that,” admitted Twilight. “But then... wait. I couldn't have done that. I saw their whole battle before, with Zecora's potion. Since I didn't see myself -”

“Time,” snapped the Doctor, “is not as linear as you think. A few minor things might have changed in your memories, anything bigger we could have gone on to sort out on a case-by-case basis.”

“Soooo... you can't sort out whatever problems Twilight just caused?” asked Spike.

The Doctor snorted. “We've done what we can already!”

Spike blinked, twice, and raised a claw to tap on his chin. “I'm... not quite seeing the problem,” he admitted. “What exactly did Twilight cause?”

The Doctor pulled down a particularly large lever with his mouth, and then stepped back from the controls. Twilight could hear the strange sound of the TARDIS launching. “Paradox,” he said.

“I caused a paradox?” asked Twilight.

“Not a paradox,” said the Doctor. “Paradox. Big grey stallion with a time machine on his wrist. You caused him.”

Twilight and Spike shared a look of mutual bafflement.

“How?” asked Twilight. “How could I have possibly caused him?”

The Doctor threw his forelegs up in the air. “Oh, for crying out loud, do I have to spell it out for you?” he asked.

“Um , yes please?” said Spike.

The Doctor glared at Spike, but complied. “Paradox,” he said, “is a time loop.”

“He's what?” asked Twilight.

“A time loop. Round and round he goes, repeating the same events time after time after time. He doesn't have a beginning, he doesn't have an end, he just goes around through the same set of actions again and again and again! First he finds himself in Discord's era, he loses his time machine and then manages to wait around until Discord's defeat, rebuilds the machine, travels to the future to try to kill you in retaliation for your having trapped him in Discord's time, goes back to try to kill you as a baby, then tries to crash my TARDIS when it's damaged, then goes further back to try to arrange Nightmare Moon's victory so that there isn't even a world for you to exist in... and then you do something completely stupid and send him back to Discord's era, starting the whole loop over again!”

Spike frowned and raised a claw. “Wouldn't he get older every time round the loop, until he died of old age?” he asked.

“Weren't you listening?” asked the Doctor. “He doesn't age he doesn't learn he can't be injured – he doesn't change.”

“Wait a minute,” said Twilight. “You're saying he tried to kill me in retaliation for me sending him back to Discord's time? Doesn't that mean that Discord managed to change him – at least his goals?”

“No, it does not,” said the Doctor, firmly. “His goal was always to kill you, and thus to not exist. In all of his cycles, that never changes.”

“Soooo...” said Spike, “does that mean that every time he gets out of Discord's era he's going to make a new attempt on Twilight's life?”

“No,” said the Doctor. “It means that every time he gets out of Discord's era he's going to make the exact same attempt on Twilight's life. The same place, the same time. We know she survives it.”

“That memory,” said Twilight, with sudden realisation. “When we were in Discord's era, and he remembered where Discord was going to throw those fire balloons. It was never your memory – it was his own memory, from a previous loop!” She frowned. “But wait, does that mean he was learning from his own memory?”

“No,” said the Doctor, “he didn't learn anything that he hadn't already – and always – known. If you had just been able to keep your hooves off that strawberry milk flower, none of this would ever have happened! You would have been able to live out your entire life without having to deal with any crazed time-travelling assassins, I would never have crash-landed and been forced to take on an identity as a clockmaker, and Paradox wouldn't be trapped in the age of Discord for all eternity! Aside from that, everything would have been exactly the same, or at least fixable!”

“Oh, I don't know about that,” said the flower still in Twilight's mane, speaking in Discord's voice.

There was a long moment of silence.

“You don't need to look at my flower like that,” said the flower, the petals moving like a mouth. “I still can't time travel, this is just a recording. And no, I can't hear you, but I do have access to Twilight's diary, and she certainly wrote about this conversation in detail! Anyway, I just wanted to say that, when you get back to the present, you might just want to talk to me about a number of side-effects of Paradox's existence that you're not aware of quite yet.”

The flower grinned in the approximate direction of the Doctor, and then fell limp, its message delivered.

Spike shakily raised one claw to point at it. “Are you really sure it's a good idea to keep that thing in your mane?” he asked, nervously.

Side Effects

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp

A large blue most-certainly-not-an-outhouse faded into view in a remote apple orchard near to Ponyville. Two ponies stepped out, followed by a baby dragon.

There was a thump from behind the TARDIS.

“Twi?” asked a familiar voice. “Is that... really you?”

“Applejack?” Twilight turned around. “Yes, it's really me, but – I haven't been gone for that long, have I?”

“Only two cotton-pickin' weeks without warning!” said Applejack. “Celestia's got royal guards huntin' up an' down Equestria f'r you! Luna's bin huntin' through dreams f'r a clue! Even Discord couldn' find you! Where've you been, Twi?”

Twilight sighed. “It's a long story, and I'd far rather tell it just once. Could you get the girls together in the Friendship Castle? And Spike, could you send a message to Celestia so she stops worrying?”
Spike saluted. “Nooooo problem!” he said.

* * *

“...and that's when we appeared in Applejack's orchard,” finished Twilight. She looked over at her audience – five former Bearers of the Elements of Harmony, two Princesses*, a baby dragon and a full-grown draconequus.

Luna turned to glare at Celestia. “You knew,” she said.

“Well, I think that was a fascinating tale,” said Rarity.

“Yeah, it was awesome!” agreed Rainbow Dash.

“I did know that she'd be time-travelling at some point,” said Celestia, “but I had no idea that it would be now!”

“Ah'm a little curious,” said Applejack, “about these here side-effects that that there flower was on about.” She turned to look at Discord, and raised an eyebrow. “Would you like t' elaborate, perhaps?”

“Oh, I think I'd rather like to know, too,” said Fluttershy's voice, from under the map table. “Um, if that's alright with you, I mean.”

“Oh, where to begin?” Discord rolled over, lying on his back in mid-air. “Well... you do realise, of course, that I was quite a different Draconequus back in those days, right?”

There was a chorus of nods from around the table, and a squeak from underneath it.

“Back then,” continued Discord, “I never really saw ponies as, well, individuals in any way. Every pony reacted to me in just about the same way – you know, screaming, running, that sort of thing. But there was one – just one – that I couldn't break. No matter what I did to him, no matter how I did it, he survived – everything. It was just a pity he had such a terribly orderly personality. Boring, boring, boring. So, I had this idea... if I could just recreate his untouchability – put his invulnerability on some pony that actually did something interesting on occasion – then maybe I could have a pony worth talking to.” Discord's grin widened. “Of course, for best results, they'd have to be trying to fight back against me – their pitifully amusing attempts to defeat me would provide some small entertainment over the years – and they'd have to be intelligent enough to keep coming up with new ways to defeat me...”

“...are we going to have to beat the stuffing out of some ancient indestructable monster you made once?” asked Rainbow Dash, folding her forelegs.

Discord promptly burst into laughter.

“...did I say something funny?” asked Rainbow Dash.

“Not intentionally,” said the Doctor. “I'm pretty sure that he -”

“No, no, no, no,” said Discord, “I want to tell them!”

“Tell us what?” asked Rainbow. “Where to find this giant monster?”

Discord howled with laughter again.

“Clearly it's a very funny monster,” said Pinkie, narrowing her eyes.

“Does it... present any sort of danger to Equestria?” asked Twilight.

“Only to cake,” sniggered Discord.

“Could it take over the country?”

Discord fell over laughing again. “It – it – it already did!” he howled.

“What, while we were in here?” asked Twilight. “We'll have to hurry! Girls! Formation! Discord! Will it come after us?”

Discord's laughter redoubled. “It's, it's, it's already in the room!” he yelled.

All six former Bearers of Harmony crouched down, standing in a circle, surrounding the Princesses, facing outwards, and looking for any threat. Even Fluttershy had abandoned her nice, comfortable spot under the table.

“This has gone quite far enough,” said the Doctor, firmly. “If you don't tell them, Discord, then I will.”

“Oh- heeheehee – alright then,” said Discord. “I found a way to combine the magical traits of all three pony races, added in a few little touches of my own, and created -” he waved his lion paw at the Princesses - “the first alicorns.”

There was a long and complete silence. The first to break it was Luna. “Thou didst not!” she objected. “Mine sister and I were born from a family of earth ponies!”

“Did they never tell you?” asked Discord. “You two weren't born, I just had a stork deliver you to their doorstep.”

“A stork?” asked Rarity. “That's – rather cliched for you, isn't it, darling?”

Discord shrugged. “Where do you think that story started?” he asked.

“So...” Twilight frowned. “You made Celestia and Luna?”

Discord nodded. “Their futile attempts to stop me were the best entertainment I'd had in centuries!” he said, still grinning. He reached out with his eagle claw, and picked the flower from Twilight's mane. “And then, of course... one day... they actually succeeded! It was brilliant! I mean, I'd taken the brunt of their futile attempts a few times before – it was just so much fun to pretend it worked and then turn up a few days later and ruin everything for them again! I'd never expected them to actually do it, though...”

Discord sighed, and bit the top off the flower. “It was brilliant for the first week,” he admitted. “After that, it was just tedious and uncomfortable. Did you know, I developed an itch on my nose after the second week? For one full thousand years, I couldn't scratch it! Most annoying.”

“So, um...” Fluttershy squeaked nervously. “If you don't mind me asking... what did you do then?”

Discord shrugged, and tossed the rest of the flower into his mouth. “Nothing much,” he said. “I spent a few centuries trying to figure out how to turn this charming specimen -” he leaned over and pinched the Doctor's cheeks - “into Paradox. And, of course, testing out that spell was one of the first things I did when I got out!” He frowned at the former Bearers. “To be fair,” he continued, “you lot weren't quite as invulnerable as Paradox, but I don't think it was that bad, for an initial attempt...”

*Cadance had been unable to make it in time, but Spike had sent her a reassuring note.

Pinkie Pie

Who can I talk to about this? Who can I - “Beware the Sun”. Is that Celestia? No, surely not. If I wanted to warn myself about Celestia, surely I'd call her by name. Betrayed by someone close to me? Someone not somepony? And who mustn't I tell?

Twilight hovered uncertainly at the entrance to her castle. The idea of trying to think of her close friends as potential betrayers was... worrying. But somepony had clearly thought that message important enough to risk a time spell on, so she clearly had to take it seriou-

“HIIIIIIIIIIII Twilight!” cried a cheerful voice from right next to her.

Twilight jumped, turning quickly to face the voice. “Er, hi, Pinkie.”

“Wow, your eyebrows grew back quickly!” said Pinkie.

“Er, what?”

“Here's your banana!” said Pinkie, shoving the peeled fruit directly into Twilight's mouth.

“Hrrrrrmf?” asked Twilight, chewing as quickly as she could.

“Bananas are very good for you,” said Pinkie, nodding, and peeling a second one. “They're full of potassium!”

“Hrmf, hmf,” mumbled Twilight. She swallowed the rest of her banana. “Pinkie, what are you – hrmf!”

“No time!” said Pinkie. “Bananas first!”

“Mmmmf!” objected Twilight, chewing rapidly.

“You shouldn't've gotten rid of your flower, though,” said Pinkie, with a nod. She was already peeling a third banana. “I liked your flower. Did I ever show you my flower?”

“Hrmf?”

“Yeah, I've had it for years,” said Pinkie. She reached into her mane, and pulled out a clearly fake, plastic flower with a large bulge at the bottom of the stalk.

Twilight, still chewing, raised one eyebrow.

Pinkie pointed the flower at Twilight and squeezed the bulb, with the result that the flower sprayed water in Twilight's face.

“Hrrrrrrmf,” grumped Twilight. She swallowed. “Pinkie, if you -”

Pinkie promptly stuffed the third banana in Twilight's mouth.

“HMMMMMMF!” objected Twilight, frowning at Pinkie. She charged up her horn, and vanished with a *pop*.

Pinkie nodded, and trotted into the Friendship Castle, pulling another bunch of bananas out of her mane. “Hey, Spike!” she called out. “Do you want a banana?”

* * *

With a *pop*, Twilight appeared on the other side of Ponyville. And on top of everything else, Pinkie's being extra Pinkie today...

It was at this point that she spotted a familiar pony, just re-entering his clock and watch repair shop.

Of course! I can ask him! Surely he wouldn't've told me not to tell himself?

She quickly finished chewing and swallowed her last banana, and then trotted over to Time Turner's cottage and knocked on the door.

Epilogue

Epilogue: The Doctor

“No!” said the Doctor, firmly.

Twilight turned her head slightly to the side, her eyes wide.

The Doctor shook his head. “That's not going to change my mind,” he said. “Do you know what happens if you meet an older version of yourself?”

Twilight blinked. “Um... I did once... wait, actually twice...”

“Well, then I guess we can consider ourselves lucky there's still a future and a past!” snapped the Doctor. He sighed. “I'm sorry,” he added. “That was uncalled for.”

The Doctor took a deep breath. “In effect,” he said, “there are ways to meet your future self safely, without causing trouble. But there are no ways to guarantee that such a meeting would be safe, especially if your future self has reason not to cooperate. And if it goes wrong, it can go very wrong. Now, normally, when I have a companion accompanying me, I avoid the whole problem by simply going far enough in the future that they would have long died of natural causes. In your case, that's impossible – you're an alicorn, you likely won't die unless you're deliberately killed. And with your power and social position, there's not a corner of Equestria where you couldn't go if you wanted. If I were to travel with you, then, for safety reasons, we'd be limited to the past. And going back to – or through – the time in which Discord ruled Equestria would be dangerous for other reasons. So we'd be limited to wandering up and down a single millennium. I just... want to explore further than that. I want to see what happens to Equestria in the far future. Besides, you were gone for two weeks, here; next time, it could easily be a year.”

Twilight sighed.

The Doctor smiled. “Hey, don't worry,” he said. “You'll probably be seeing quite a lot of me, over the years. In fact... do you think you would be willing to invite me to your thousandth birthday party?”

Twilight blinked. “Ummmm... sure.”

The Doctor winked at her. “See you there, then!” he said, stepping into the TARDIS and closing the door.

vworrrrrrrrp... vworrrrrrrrrp...vworrrrrrrrrrp