Spectrum

"Twilight!"  Spike called eagerly from the library stairwell, "You've got a letter from the princess!"

"Okay, Spike. Just give me a minute to finish up on something, okay?" Twilight called back distractedly from her bedroom. Her eyes traced over her most recent project for a few moments before her stomach growled, breaking her concentration. Twilight sighed. "Okay, I guess I can finish this later. Not like I'm getting much done right now anyway." The purple unicorn blinked and headed for the stairs that led down to the kitchen and food. Her glowing horn closed the curtains behind her, shutting out the worst of the intense afternoon sun.

"Hi, Twilight," Spike greeted her as she entered the room. He pushed a hay sandwich toward her. "I figured you'd probably be hungry when you came down, so I made you lunch."

Twilight gave the little dragon a tired smile. "Thanks, Spike, you're the best." She took a few bites of her food, then remembered the note Spike had told her about earlier. She looked around the kitchen for a moment before spotting it lying on a counter. She used her horn to pull it toward her and open it, and began to read.

My dearest student Twilight Sparkle,

I noticed in your most recent letter to me that you have begun to undergo a study of teleportation. I am pleased to hear that you are continuing to put your wonderful mind to new and exciting things. I know another unicorn here in Canterlot who also has a great interest in this topic, as well as a great talent for it. If you do not mind, I would like to send her to stay in Ponyville and help you with your research. She has already expressed interest in doing so, if you will consent, and I think she may be able to help you.

Your teacher,

Celestia

P.S. This pony can be a bit eccentric at times. If you accept her offer, please have patience with her. I truly believe you two can help each other.

Actually, another pony to help figure things out would be nice. At the very least, they could help look over what had already been done to make sure there were no flaws. "Spike, take a note please."

"With pleasure, Twilight." Spike hopped off of his seat and grabbed a quill and some parchment, then looked to Twilight to start dictating.

"Dear Princess Celestia. I am excited to know there is another unicorn who shares my interest in the magic of teleportation, and would be glad to work with them. I would be glad to let her stay in the library with me if need be, and I look forward to her arrival. Your student, Twilight Sparkle.

"Send it."

Spike rolled up the parchment and blew on it, and it disappeared in a ball of green flame. "Done."

"Thank you, Spike. Now we just have to wait and see what she says."

A knock on the library door ended the conversation, as Twilight stood up and trotted over to it. Opening the door, she was amazed to see none other than Rainbow Dash standing outside, looking as out of place as any pony Twilight had ever seen.

"Wow. What brings you here, Rainbow? You're not a pony I'd expect to see at the library."

"Yeah, yeah, I know I'm not. Can I come in?" Rainbow Dash looked around nervously.

"Why so nervous? Still afraid someone's going to see that you're reading?" Twilight smirked.

"I'll take that as a Yes, Rainbow Dash, of course you can come in. Make yourself at home." Rainbow darted around Twilight and through the door almost faster than Twilight's eyes could follow.

"Oookay. So is that a yes on the reading thing?"

"Not really." The Rainbow who responded was visibly more relaxed than the one who had been standing outside. "No, I'm afraid they're going to see what I'm reading."

"And what exactly is that?"

"Well, a few days ago, I was passing by the school when I heard somepony telling a story." She paused for a moment, working up the nerve to continue. Twilight, thinking she was done speaking, jumped in.

"They were telling a story? And this was important enough to send you of all ponies to the library?" She raised an eyebrow. "There has got to be more to it than that."

"I'm getting to that, okay?" Rainbow snapped. "Anyway, the funny thing is that it was the story of the Lost Skykeep and for some reason my mind-"

"Wait wait wait. The story of what now?"

"The Lost Skykeep. What, haven't you heard it? It's one of the first stories I heard as a filly."

"Maybe it's a pegasus thing. I learned about the skykeeps in Equestrian History, of course, but I've never heard of that particular story. Care to fill me in?" Twilight was intrigued now. She thought she'd heard every fillytale there was to hear in the various periods she'd spent at the daycare center in Canterlot while her parents were at work or shopping or whatever they happened to be doing, but she'd never even heard of this one.

"Sure. I don't remember it word by word or anything, but the gist of it is this." Rainbow took in a deep breath, and Twilight perked up her ears, knowing that the whole story was about to get thrown at her in one big breath.

"So there was this pegasus named Sky Sprint and she had a friend who I forget the name of but they were a unicorn and one day this unicorn friend did some funny magic thing and ended up falling out of the sky and Sky Sprint went to save him... Or her, I can't really remember that either but anyway she went as fast as she could and got to him... Or her oh whatever the unicorn's a guy now and just as she was getting to him he did some funny magic thing and they ended up in this lost skykeep and there's more but it's not important and I really need to breathe." By now turning purple from lack of oxygen, Rainbow gratefully broke off talking and sucked in huge gulps of air to recover.

Twilight giggled. It was actually kind of cute to watch Rainbow Dash get all excited when she was talking like that. She had a tendency to throw her forelegs around wildly, acting out whatever she was talking about. Not that she would ever say that to Rainbow's face- "cute" was not Rainbow's speed at all.

"Okay," Twilight found herself saying, "so that's the story. Now, what did your mind do for some reason?"

"I'm getting there, just gimme a sec."

One eyebrow raised, Twilight stared at Rainbow for a few seconds until she started to talk again.

"Okay. I'm okay now. So, I just realised when I heard that story again- gosh, it must've been the first time in years I'd heard it- that Sky Sprint is the same pegasus from the Sonic Rainboom legend."Rainbow Dash smiled expectantly, as if waiting for Twilight to come to some sort of earth-shattering conclusion.

Twilight had come to no such conclusions, however, and was now even more confused than she had been when the conversation began. "Hate to break it to you, Rainbow Dash, but I have no idea how or why that's significant. Care to explain?"

Dash's face fell a little bit. "Well, it's all kinda theoretical right now, so I'll spare you the details. Really, I just want to find a copy of the story so I can check it in a bit more detail, make sure of a few things."

"Okay. Sure thing, Rainbow. What was the name of the story again? The Lost Skykeep?"

"Yeah."

"Okay. Hey, Spike, could you check under 'L' for me? I'll check 'S'."

Spike moved a ladder over to the L section. "Hmm, Lost Skykeep Lost Skykeep Lost Skykeep... Lost Skykeep!" He plucked the book off the shelf and hopped down the ladder to present it to Rainbow Dash.

"Thanks, Spike."

"No problem. Uhh... If you don't mind me asking, what exactly is a skykeep, anyway?"

Rainbow Dash put the book under her wing. "A skykeep is basically a castle with a cloud-walking spell on it. They're built on clouds and just kind of float around. Think of Cloudsdale for unicorns and Earth ponies. They started making them about nine hundred years ago. At some point, one fell off of the cloud it was on, somehow. It landed on a town and killed a bunch of ponies. Princess Celestia ordered them all torn down and outlawed their creation pretty soon after that. One, the one in the story, just vanished. No trace, no trail, nothing. No one  ever found out where it went."

Rainbow turned to leave, then stopped and looked back over her shoulder at Twilight. "Hey Twilight, if I get beyond the hypothetical stage, wold you mind helping me out? I'm probably going to need it, because this might turn out being a scientific thing. I'm not very scientific and... You kinda are."

Twilight beamed. "Of course, Rainbow, just ask and I'd be glad to help you."

Rainbow Dash shot her a grateful smile. "Thanks, I really appreciate it Twi'."

"Not a problem at all Rainbow. Not a problem at all."

Rainbow walked calmly to the door of the library. Then, in a blur of motion, she opened it, darted outside, and flew off, closing the door with a bang. Spike, who was back at the lunch table and was just picking up his drink to take a sip, jumped at the unexpected noise, inadvertently splashing water all over his face. He threw his hands in the air in a gesture of defeat. "And here I thought the day might go off without any accidents for once."

Twilight laughed and used her magic to refill Spike's glass. "Sorry Spike."

• • •

That night, Twilight tossed and turned in bed, unable to sleep. Her equations and theories wouldn't stop running through her head, looping over and over endlessly and getting her nowhere. She almost growled in frustration; it wasn't like her to have this happen- usually she was able to put her work out of mind with ease when she wanted to. Like, for instance, when she wanted to sleep. Then again, it also wasn't like her to get stuck on a problem for so long. Twilight was used to being able to work her way through an entire theory in a day or two, sometimes less. She'd been stuck on the same part of this teleportation spell for almost a week, and it was finally starting to get to her as she slowly ran out of ideas.

Twilight had a lot of questions, and far too few answers. How could a pony be standing somewhere, use a little magic, and then suddenly be standing somewhere completely different? Why did it take the same amount of magic no matter how far away the start and end points were? Hay, what was the spell even really doing? None of it made sense!

Twilight breathed out, forcing herself to be calm. Soon she would have a partner, someone who could help her figure this out. Hopefully they would be able to give some sort of suggestion as to what to do. Tomorrow was a new day.

While she waited for the new pony to show up, she decided, she would let the problem lie. That might help make things a bit clearer. Maybe she would do some research on the pony who had come up with the spell in the first place.

Twilight found herself hoping the spell had frustrated its creator just as much as it was frustrating her.

She shook her head to clear it of that kind of thinking- she knew she didn't really mean it, but it still wasn't nice- and finally managed to fall asleep just as the first traces of predawn light began to creep over Ponyville.

• • •

"Twilight, get up. It's almost noon."

"Wha?" Twilight mumbled, blinking sleep out of her eyes as she turned her head away from the sunlight pouring in through the windows.

"Twilight, you have to get up now, we've got a visitor."

"A visitor? Sorry, Spike, just give me a second to wake up properly; I didn't get much sleep last night."

Twilight yawned. Then, feeling coherent enough to understand what she had missed a moment ago, she asked, "So, what was that, again?"

"A visitor. I've never met her before, so I think she's the pony Celestia was talking about- you know, the other pony who was into that teleporty stuff you've been working on."

That woke Twilight up. "What? She's here? Already? But I, I'm not ready, I haven't even cleaned up or anything!"

"Relax," Spike said. "She seemed friendly enough,--"

"Okay. Okay," Twilight said to herself, forcing herself to calm down. "Even if she minds the mess, that's okay and there's nothing to do about it now. Well, let's go say hello, then." She moved toward the stairs, Spike following slowly behind her.

"... if just a little bit weird," Spike muttered as he hopped down the first step.