It was a dark and stormy night. Not because anything particularly ominous way going on, but simply because a low pressure front was passing over Ponyville and the weather was reacting accordingly. That wasn't to say that ominous things weren't going on. They'd been going on for weeks. They just had nothing to do with the weather.
Half a mile outside Ponyville proper, an ancient and twisted pine tree finally gave up its tenuous grasp on the soil and toppled over in the wind, snapping a series of power cables in a brief display of crackling sparks. Half a mile away, every light in Ponyville went out at once.
Every light, except one.
The Golden Oaks library shone like a lighthouse, briefly the sole source of illumination for miles in any direction. Ponies quickly began to light candles in their windows, which hovered around the library in the darkness like fireflies around a lamp. Inside the library sat an abandoned cup of coffee, now cold, atop a busy wooden desk which was carved into the wall of the tree. Twilight, sleeping head down on the desk, was woken up by a brief banging on the library door downstairs.
*bang bang bang*
"Whu-?" Twilight wiped an encrustation of drool from her cheek and sat up, a piece of the evening's paperwork stuck to her cheek.
*bank bang bang*
Even in her dazed state, Twilight realized that the view from the window wasn't quite right. It was completely black. Something must have happened: there was always somepony up in Ponyville.
*bang bang bang*
Oh right. That.
Twilight slid groggily off her chair and plodded over to the library door. As soon as she removed the lock the door swung open in the wind and she was confronted with three bedraggled figures: one yellow, one pink and one white.
Twilight's hair blew back in the wind, the blast of cold air waking her rather forcefully.
"Hi Twilight!" Screeched Pinkie, desperately trying to make herself heard over the wind. "It's windy tonight!"
"Hi, girls! What's going on?"
Twilight watched as Rarity presumably explained the situation, but the words were lost in the storm like spittle in a hurricane. Given the amount of water which was currently soaking into Rarity's normally pristine coat some literal spittle may have been lost too.
"I think you should come inside!" Twilight yelled.
"What!?" Pinkie yelled.
Twilight gestured frantically with a hoof and her friends stepped from the porch into the library. With a tug of magic, Twilight pushed the door shut against the storm and sealed the biting rain outside to fight against the wind for dominance. Twilight breathed a sigh of relief.
"Rough night, huh?"
"You don't know the half of it, darling." Rarity replied, shivering. "Do you have any tea?"
Twilight nodded. "I'll put some on. You two want anything?"
"Hot chocolate with sprinkles please!" Pinkie yelled. Fluttershy merely smiled gratefully and nodded. Twilight trotted towards the kitchen but called back over her shoulder.
"Make yourselves at home. What's going on out there anyway?"
Rarity climbed carefully onto the couch but was immediately displaced as Pinkie landed on it like a sack of rocks. Rarity rolled her eyes as she picked herself up off the floor. "The power's gone completely. There I was, curled up quite happily in bed with my latest roma- er, uh" Rarity stuttered as she tried to recover the sentence "book of poetry?" she ventured, blushing, "when the lights died completely! I had no idea that you had your own generator, darling."
Twilight walked back in from the kitchen and set down four cups from her magic: three teas and one sugar-filled monstrosity. "Oh yes, I got it quite recently." She frowned. "Did you really need to finish the poem that badly? Couldn't you just wait until morning."
Rarity's cheeks betrayed her again, but a lifetime of failing to read social queues hadn't prepared Twilight for detective work. "It was just so thrilling..."
Twilight beamed, apparently satisfied. "I know what you mean. I just can't put a good book down sometimes."
"Yes. Definitely." Rarity replied.
"Especially those really steamy romance novels you keep at the boutique."
"... What?" Rarity deadpanned.
Twilight frowned again. " The ones in the boxes. I always assumed they were for customers to read while they waited.
"The boxes." Rarity's expression remained perfectly emotionless.
"Yea."
"Which boxes?"
"Oh you know." Twilight offered, helpfully. "The unmarked sealed iron ones under the floorboards in the locked back room with the sign on the door saying 'lethal biohazard'."
"Oh. Those boxes."
"Yea." Twilight beamed, oblivious. "I couldn't find the biohazard though; I looked for hours. Anyway," she continued, "what're the other two of you doing here?"
Twilight turned to Pinkie, who was slurping violently as her tongue cleaned out the bottom of her mug. "Hmm?" she offered, glancing up. "Oh! I couldn't start the oven to bake my cupcakes so I thought I'd bring them here and borrow yours!" Pinkie replied, pulling a tray of cupcakes from her mane.
Twilight frowned again. "Don't you have a gas oven?"
"Yea! Mr Cake said never to leave it on but tonight I couldn't even get it started!"
"You did turn off the gas flow though right?" Twilight hazarded.
"What gas flow?"
There was a distant rumble, as of a very large number of dragons waking up in a very small box. Twilight weighed the probability of being able to do anything about the inevitable fire, which would almost certainly be put out by the rain, against the probability of Pinkie making things worse by trying to help.
"Don't worry about it." She offered. "What about you, Fluttershy?"
Fluttershy looked up, still cradling her tea like a lost baby bird. "It was scary at home in the dark." she squeaked.
"Ah."
Rarity lay down her teacup and glanced around at the library's bright lights. "Why do you have generators in the first place, Twilight? Surely power cuts can't be all that common."
Twilight beamed, sensing an opportunity for a lecture. "They aren't, but I have dozens of machines in the basement which can't afford to run out of power. For example-"
Rarity decided to shut the lid on Pandora's Wikipedia page before it could get into full swing. "Oh I don't doubt it, darling! But surely they must be expensive to run?"
Twilight looked crestfallen, but perked up again at the second question. "Not at all. Actually, they're so cheap I use them all the time now, not just when the power's out."
Rarity goggled. "What do they run on?"
"Souls." Twilight beamed. "I had to make the generators myself of course, but once they get going-"
Rarity interrupted her. "I'm sorry, come again?"
"I had to make the generators myself."
"No, before that."
"They're cheap?"
"After that."
"Souls?"
"Souls?"
"Souls."
Rarity was briefly the mother of a pregnant silence. "What do you mean souls?"
Twilight looked puzzled. "You know, the immortal ethereal energy within all creatures. We've all got one. Well, except for Spike, anyway. Oh, and me. I had to leave mine behind in Hell after I went to visit the devil." She smiled. "Come take a look downstairs!"
Twilight ambled over to a small door and pressed her horn to the old iron lock set in the wood. The door opened with a click and, hesitantly, the other three ponies made their way over. The door opened onto a flight of descending stairs lit by an eerie blue glow. Twilight began to descend into the basement and the others followed. Fluttershy looked terrified, Rarity was staring, only Pinkie Pie seemed unfazed, bouncing quite happily down the stairs. The blue glow was coming from a large Machine: it took up one whole wall of the basement and emitted, along with the light, a constant low level wailing which made Rarity's skin crawl. It's outlandish appearance simply demanded the capital letter.
"How can you use souls to power your coffee maker?!" Rarity shouted, both out of stress and a need to be heard over The Machine.
Fluttershy's trembling voice was faintly audible in the background.
"And what do you mean 'except for Spike'?"
Twilight seemed unfazed. "It's really quite simple. You see, souls are eternal but they can still exert force on objects; knocking over plates or making blood ooze from the walls or suchlike. So I figured all I needed to do was get a hold of some souls and get them to push on turbine blades in my basement for all eternity." She looked pleased with herself. "It's a remarkable piece of technology. I'm rather proud of it."
Behind Twilight, red liquid began to ooze from the cracks in the basement wall. Pinkie reached and took some on her hoof, licking it.
"Tomato juice?" She exclaimed, frowning.
Twilight looked embarassed. "Yea. I stopped it from oozing blood but I'm still working out some kinks."
Rarity was just staring. Eventually she managed, "Twilight. I don't mean, 'How are you able to use souls as fuel', I mean, and I cant believe I need to emphasise this, 'Have you considered the ethics of trapping actual dead pony souls in electrical generators for your own personal gain?!'" Rarity stopped to breathe. "Where do you even get them from anyway?"
Faintly, Fluttershy tried again.
"And, um, what do you mean 'except for Spike'?"
Twilight tapped her chin with one hoof, frowning. "Huh. I suppose I'd never really thought about it." She shrugged and smiled. "That said, they're probably better off here then in Hell."
One of Rarity's eyelids quivered. "Hell?" She queried, apparently no longer surprised.
"Yea," Twilight continued, "it was really hot down there, and the constant screaming gave me a headache."
"Twilight. Have you been stealing souls from... Hell?"
"Oh no!" Twilight looked horrified. "I buy them. The Devil gives me a really good deal, given how long they last."
"That's insane!" Pinkie interrupted.
"Pinkie's right, Twilight!" Rarity cried. "How can-"
But Pinkie ignored her. "There's so many more good ponies than mean ponies! Celestia must have way more souls to sell than the Devil!"
Twilight looked thoughtful. Rarity looked horrified.
"What do you mean, 'except for Spike'!" Fluttershy yelled. The other three ponies looked at her, shocked. She cowered under their gazes, blushing. "Um, nevermind."
Rarity shook herself. "This is absurd, Twilight. I simply have to tell the Princess!"
Twilight jumped. "No! You can't do that; The Machine isn't finished yet! They'd see all the problems and think I'm no good!"
"I'm sorry, Twilight." Rarity turned up her nose and began to march up the stairs. "I just can't let this go on!"
Fluttershy followed her meekly, still blushing. Twilight wrung her hooves, caught between protecting her image and not arguing with her friend. The door slammed shut, Rarity calling out for Spike to send a letter, while Pinkie wandered over the The Machine and started poking at a spinning chamber with her hoof. An arc of energy earthed itself onto her hair and coated it in ectoplasm which she licked at happily.
"Pinkie!" Twilight broke out of her fretting. "I need to fix this all before the Princess arrives! Stop messing with the Soul Centrifuge!"
"Oh don't worry, Twilight! I'm sure the Princess will love it." Pinkie pored over the surface of The Machine. "Is there anywhere I can fit cupcakes?"
A blinding light and heavenly chorus cut off Twilight's response, both mares' manes flying out in the ethereal wind. Dual wings unfurled from the centre of a pulsing nexus of light and the Elder Diarch of Equestria ascended into the air, starfire burning in her normally kind eyes. Celestia's arrival was subsequently diminished in impact when, unused to arriving within a room, she hit her head on the basement ceiling and dropped to the floor, heavenly chorus and blinding light flickering briefly as she recovered.
"Twilight!" Celestia boomed, discreetly rubbing her head. "What terrible actions have you taken in my absence?!"
Rarity poked her head into the basement from the top of the stairs, watching the scene unfold. She had never before seen Celestia so angry.
Twilight withered under Celestia's stare. "Wh- But- I- I didn't-"
"Silence!" Celestia roared. "Is this machine as your friend described it? The enslavement of pony souls for mere power?"
Twilight looked like a deer which had moved out of the path of an oncoming train only to be confronted with a crashing helicopter. "I- I thought it would power the world, Princess!" She managed. "I thought only of others! Truly-"
"Why did you not come to me for the souls, Twilight?!" Celestia cried.
Twilight paused. Rarity stared. The wailing of The Machine was replaced, according to some fundamental law of the universe, by the chirping of crickets.
"What?"
"They're just lying around!" Celestia whined, voice losing its tone of regal judgement. "I mean you could have just asked! I was waiting for somepony to figure out a good use for the damned things." She leant in close. "What deal has the Devil cut with you? I'll double it."
Twilight shook herself one more time, looked thoughtful, then responded.
"Triple." She said. "And I'm going to need a new soul for myself."
