Act II: The Twilight Hour
Part 1 - Science in the Library
Rainbow Dash watched, bewildered, as the stallion with the hourglass mark practically danced across the library. His brown mane hung over his head, bobbing with each step he took, of which there were many. Everything about him seemed to be at a quicker pace than the world around him, as if his heart beat twice as fast, or perhaps twice as hard.
It was the day after Twilight had taken the other ponies down to the lake to explain the truth. In the mean time, Applejack, who seemed to have taken over as the leader of the group and representative of their Twilight, had permitted the other Twilight access to the lab in the library's basement, on the off chance that something there would help them discover a way to cross over or retrieve Twilight. Fluttershy had gone into the Everfree forest to talk to Zecora, since it appeared the zebra knew more than she let on.
While it seemed Zecora knew about the existence of the 'moonland', as she had chosen to call it, she refused to offer any advice on crossing over, and attempted to discourage the ponies from any attempts to do so. "Remember what happened the last time," she said, and the image of the twin graves again passed through Fluttershy's mind. So far, all of their efforts had been fruitless. Rainbow hoped that the Doctor would change that. Pinkie Pie had managed to contact the Doctor by a means Rainbow Dash didn't know, and Pinkie refused to explain.
"It's complicated," said Pinkie Pie when Rainbow Dash had attempted to press the issue. "You can't just walk up to his home and knock; it doesn't work that way." Eventually, Rainbow relented and allowed Pinkie to do whatever she needed to do to reach him. Fortunately, it seemed he wasn't busy, as he showed up unexpectedly in Ponyville the very next day, albeit with no luggage and no form of transportation.
Now, Rainbow Dash stood in the corner of the library with the others, listening to their newest guest. The way he talked was by the far the most interesting part of him, Rainbow Dash decided. He spewed out details almost as fast as anypony around him could process them, following one train of thought before jumping onto the next. The rhythm of his speech was inconsistent, passing quickly over the minor details but becoming slow and heavy for anything the Doctor wanted to put emphasis on.
"Let's see what we're working with," the Doctor said to himself. "A library inside a tree. Interesting, a library tree. A tree of knowledge. Bit on the unfortunate implications, don't you think? Also, very flammable. Not a good dragon home. You might want to do something about that." He paused, inhaling deeply. "Oh, but you have! An interesting odor, the smell of magic but no resin. A stasis charm, probably, put on the whole tree. Makes it fireproof. Rot-proof, too. Well done, Twilight, was it?" He held out a hoof to the equally bewildered Twilight. "I'm the Doctor. Just the Doctor."
Twilight took the hoof and shook it. "Twilight Sparkle. Can you really tell that just by smelling?"
The Doctor paused, in thought. "No, not really, not with certainty. Hold that thought for a moment." He cantered over to the wall and gave it a solid lick with his tongue. "Definitely a stasis charm," he concluded.
Twilight stared at him incredulously. "You know an awful lot about magic for an earth pony," she said.
The Doctor froze, and then he approached her slowly, his eyes slanting. "Whoever said I was an earth pony?" he asked. Twilight didn't know how to respond, but an instant later the expression was dropped and the upbeat attitude returned. "Right. So, like I said, I'm the Doctor. Official consultant to the princess herself for all matters relating to physics, temporal mechanics, and butterscotch." He removed a wallet from a satchel on his side and opened it, revealing an official looking license, his name and picture displayed prominently at the top. Twilight reached to get a closer look at it, but the Doctor quickly tucked it away again. "Stay close, follow my orders, don't wander off," he added. "That last one's important; you wouldn't believe how frequently ponies forget that don't wander off part."
Applejack looked at Pinkie Pie wearily. "What did you say ya did to make this fella owe you a favor?" she asked.
Pinkie Pie giggled and vibrated slightly where she stood. "It has to do with the the story of how Equestria was made," she answered.
Applejack stared uncertainly. "Come on," interjected Rainbow Dash. "She's just being Pinkie Pie. The point is, we have this mad pony on our side, so we might as well use him."
"Right. This mad stallion is yours," exclaimed the Doctor, drawing an embarrassed blush from Rainbow Dash. "Because I always repay my debts. It takes a while, sometimes, but I get around to it. Usually on a Tuesday; those are easy. Not a Thursday, though. I never did like Thursdays. So," and he turned to face Twilight. "Twilight Sparkle, mare of the hour. Guest, inquirer, clientèle. How can I help you?" He paused, confused by his own statement. "That's a bit generic to say. 'How can I help you?' Makes me feel like a greeter at a convenience store. I'm not used to being wanted in the situation. Sometimes, but usually it's the other ponies wandering off, followed by an awful lot of running. And most of the time somepony has to die first, making this a refreshing change of pace. But yes, questions. Ask them."
Twilight peered at the Doctor, not sure if he was in his right mind. "I was wondering," she said, "hypothetically, I mean, about the existence of other worlds."
"Other worlds?" The Doctor raised an eyebrow uncomprehendingly.
"Other realities," explained Twilight. "A multiverse, with worlds like ours, ponies like us, but different. And whether or not it would be possible to travel between them."
The Doctor frowned, suspicion clouding his features. "Hypothetically," he repeated, scrutinizing Twilight with his gaze.
"Yes," said Twilight, breaking into the widest grin she could manage. "Completely theoretical."
The pair stared intently at each other, and the Doctor, seeing the ambition and intent in Twilight's eyes, stepped back. He knew he couldn't handle the situation lightly. "No," he said firmly. "I'm sorry. I can't help you."
"But you know, don't you?" asked Applejack, forcing her way into the conversation.
The Doctor turned, irritated at the intrusion. "This isn't anything to do with you," he said, growing flustered.
Applejack trotted over to him, pushing Twilight aside. "Like hay it doesn't," she shouted, leaning in toward the Doctor, forcing him to take a step back. "One of my friends may be in critical condition, and I'm not going to just leave her. You're the Doctor, right? Then do what Doctors do. Help her."
"Yeah!" added Rainbow Dash. "You owe Pinkie Pie anyway."
"This isn't a simple request," begged the Doctor. "The gravity of what you're asking..."
Pinkie Pie, who had been listening to the spectacle with a worried look, spoke up. "Alrighty then. Tell us your name," she told the Doctor.
The Doctor froze, his eyes moving slowly until they were looking at Pinkie Pie. "What?" he said quietly.
"You heard me," said Pinkie, knowing her plan would work. "If you'd rather pay me back in some other way."
Pinkie Pie smiled devilishly at the Doctor, who was staring at the ground, swallowing and trying to stay afloat in the sea of mounting anxiety. Fluttershy, who had spent the encounter trying to stay as far away from the Doctor as possible, now moved behind Applejack, as if the sturdy earth pony offered additional protection against whatever theoretical danger Fluttershy had concocted. Twilight, also anxious, awaited the Doctor's next reply.
The Doctor's head swung up, and he clapped his front hooves together. "Right then, parallel worlds. Neighcola Tesla theorized that there were many other dimensions; they were just too small to see. Of course, he later claimed to have misplaced one of them in his trouser pocket, so Celestia knows if he wasn't just off-canter."
"You mean they really exist?" asked Twilight, attempting to feign ignorance and failing horribly. She was surprised the Doctor had changed his mind so quickly, and she decided that later she would have to ask Pinkie Pie what just happened.
The Doctor frowned, giving Twilight a sinister glare. "Don't play games with me, Twilight Sparkle," he warned. "I don't believe for a moment that this is all just theory. You have every intention of finding a way across worlds, and I see now that if I just walk away, you're going to do something reckless, that for all we know will lead to a vortex destroying Equestria."
Twilight had never considered that to be a possible outcome. "A vortex?" she asked fearfully.
The Doctor ignored her. "So yes, it's possible to cross. Yes, I will help you find a way. But I need to know everything."
Twilight sighed, relieved, and didn't notice Fluttershy escaping through the front door.
Fluttershy didn't breathe until she was far away from the library. Everything that was happening was too confusing and strange. Fluttershy had never been able to handle changes well, and now that Twilight was no longer in desperate need of sympathy, Fluttershy was slightly scared of her. The Doctor certainly hadn't helped to calm her at all. She needed something more familiar to calm her nerves.
Out of breath, Fluttershy sat down on a bench and panted. She was near Sugar Cube Corner, and she realized she had come quite a ways. She would return, when she was good and ready.
In the sky above her, Ditzy Doo, the local mailpony, circled aimlessly in her route. Fluttershy, feeling a bit lonely, called out to the other pegasus.
Ditzy circled around Fluttershy a couple of times before coming to an unsteady landing, true to her name. Fluttershy peered at Ditzy timidly but with a smile, thankful for something normal. As if anypony would call Ditzy normal, Fluttershy realized, but that was part of the pony's charm. She had a frightening appearance, as her eyes weren't always looking in the same direction. Ditzy had once admitted to Fluttershy that she couldn't always see clearly through her right eye, and that was one of the reasons she was such a poor flier. Fluttershy had wondered before what it would be like to see through Ditzy's eyes, but she never said anything, afraid she might offend. Yet, despite the disability, Ditzy never let it affect her relationships with others. She was always kind and friendly,even if what she said didn't always make sense.
"H-hello," said Ditzy slowly as she forced the word out. "You w-well?"
That was the other thing about Ditzy. She had trouble recalling words, and even more trouble saying them. As a result, she didn't often speak in complete sentences, not when a single word would do.
"Yes, Ditzy," said Fluttershy, in the kind soothing voice one might use to address a loved one. "I'm doing very well. Thank you."
Ditzy frowned at Fluttershy, sneering a bit. "N-not foal," she said, pained.
Fluttershy's jaw opened, but no sound came out. She berated herself silently. She should have known better. "Right. I'm sorry," she said. "You're not a foal. I won't treat you like one."
Ditzy nodded. "Not foal, not Derpy." She looked almost angry, a sight that looked silly when combined with her damaged eye. Ditzy's appearance always seemed precious to Fluttershy. Her mane shone in the bright morning light like a bale a hay, and while her coat was a dull gray, it always gave Fluttershy the impression that it was merely dirty, ashen, and that if she cleaned it hard enough, the beauty underneath would shine through.
"Listen, Ditzy," said Fluttershy, "Can we talk? I mean, if you're not doing something else. I need somepony to be with right now."
The gray pegasus shook her head, and her right eye suddenly swung over to the side, chilling Fluttershy. Ditzy seemed somewhat on edge. "Can't. W-work." She pointed to the satchel, filled with mail.
"Well then," muttered Fluttershy. "I'll let you get to it. Say hello to Dinky for me. She's such a gem."
Ditzy beamed, and then she suddenly frowned. Fluttershy feared she had said something wrong. "Letters," Ditzy said at last. Fluttershy feared her friend had finally lost the last of her marbles. Instead, Ditzy reached into the satchel and removed an envelope, offering it to Fluttershy. She took it. "See ya," said Ditzy. Then she took to the air, slowly, and was gone.
Fluttershy looked at the envelope in her mouth. The word 'Fluttershy' was written in purple ink on front. There was no sender written, but in the corner was a familiar symbol, a black spiral in the shape of the sun. Fluttershy opened the envelope and removed its contents, which, much to her surprise, contained a second envelope in addition to a single page. She read the page first:
My dearest Fluttershy, I hope this message finds you well.
I have a favor I must ask, and no one can you tell.
You spoke to me the day before to ask about the place
A world like ours without the brightest star in outer space.
I tell you now in confidence the story is quite true.
Which brings me back to favors that I must now ask of you.
Should you ever find a way to cross (you will, I have no doubt.)
The pony whose name is written here, I ask you to seek out.
When you do, I only ask you deliver this letter.
Perhaps the two of us can make these worlds a little better.
Indeed, there was a name written on the second envelope. Fluttershy read the note again, in case she had missed something. The 'no one can you tell' line unsettled her. What was so important about the letter that she wasn't allowed to tell anypony about it? She was tempted for a moment to open the second envelope and read its contents, as they probably contained answers, but that would be breaking Zecora's trust. Pinkie Pie had warned her about what could happen if she broke another pony's trust, and that was still true, even if Zecora wasn't technically a pony.
Instead, Fluttershy put everything back in the larger envelope and started to make her way home. She needed to drop off the letter before she returned to the others; they would become suspicious if she came back to them with it.
"Your plan is ingenious, Twilight. Projecting a cross force in quaternion space? It's brilliant. It just has one small problem."
Applejack tried her best to tune out the conversation between Twilight and the Doctor. She wasn't a stupid pony by any measure, but she knew she was over her head. They were using terms Applejack had never heard of before, and it was beginning to make her head hurt. She returned to the game of poker she had been playing with Rarity. This was where she could prove her smarts.
Rarity revealed her hand. "A full house," she announced proudly.
Applejack stared are her, dumbfounded. "And you're sure ya never played this game before," she asked.
Rarity shook her head. "My first time, I promise. Why, what do you have?"
Applejack attempted to elegantly lower the cards onto the table, but as she was only able to hold them in one hoof, they quickly fell out of her grasp. By reflex she attempted to catch them with her other hoof, but it quickly caught against the sling and the movement made her cry out. Rarity levitated the cards and returned them to the table face up.
"A pair of threes," she said slowly. "And are you certain that you are all right?"
Applejack pouted; she hated being pitied. "I'm fine," she insisted.
"How did that happen, anyway?" asked Rarity casually as she began shuffling the deck.
Applejack gestured over to Twilight frustratingly with her free hoof. "She happened," she muttered angrily.
Rarity lifted an eyebrow in surprise. "Twilight did this to you?" she asked, concerned. "Did she attack you?"
"Nah. I guess you could call it self-defense, though."
Rarity dropped the deck as her magic faltered, and she leaned in toward Applejack. "You attacked Twilight?" she hissed. "I can't believe you!"
"She ain't Twilight!" cried Applejack, defending herself. "Am I the only pony who sees that? 'Sides, you weren't there. You don't know what happened. She was going apple-brained. If I hadn't calmed her down, the whole town would have been destroyed in her fury."
"Except you failed," interjected Rainbow Dash. She had been occupying the time by playing "I spy" with Pinkie Pie.
"My turn!" the pink mare shouted excitedly. "I spy something rainbow-colored."
Rainbow Dash narrowed her eyes. "It's me, isn't it? Nothing else in this room is rainbow."
Pinkie Pie gasped in surprise. "Fine then, Dashie. I've got a harder one. I spy something wearing a hat."
Rainbow buried her forehead in her front hoof.
In the middle of the room, Twilight had laid out a diagram on the floor. "No, look," she insisted to the Doctor. "It works. I've used it before. It works fine."
"But only on small, inanimate objects, right?"
Twilight looked at the Doctor, confused. "How did you know? It's because I don't have enough, power, right?"
"No, your power level is fine," said the Doctor. Then he froze. "Out of curiosity, how much power were you using?"
"For something Pony-size? Ninety-five thousand watts for a fifth of a second."
The Doctor did the math in his head. "Assuming 250 kilograms for our pony, that's 19,000 joules.
"Is that not enough?" asked Twilight, uncertain where the Doctor was trying to go with this.
The Doctor groaned. "It's more than enough, Twilight. A lot more. Let me start over. You think you can't travel between worlds. Truth of it is, you never stop. Every particle collision sends you veering off into quaternion space. Only problem with dimensional travel is there's a wall between them that pushes you back in the opposite direction. Back and forth, like a tiny multidimensional pendulum. Only not at all like a pendulum and more like a spring. Does anypony have a spring?"
Nopony had a spring.
"Ah, well," sighed the Doctor. "Worth a shot. That point I'm trying to make, Twilight, is this." He galloped into the kitchen and returned with a plate. "The boundry between universes is strong and tough, like the walls of your home. A pony is soft and fragile and blunt, like this plate. What you're doing is trying to pierce the wall by driving the pony through it with enough force. But it doesn't matter how much force you use, because it's never going to be enough. The end result is always the same." The Doctor threw the plate like a discus, and it sailed into the wall and shattered.
Twilight became incredibly pale.
"You can send other things through because they're not fleshy like a pony, and because you probably enchanted them, hardened them first. But you can't harden a pony without killing her, so the most you can do is a sort of magic shell, which still won't soften the blow. You could send a whole army through with the amount of power you're using. But they'd all end up in pieces on the other side. Hence, as I said before, it's impossible."
"I have an idea," suggested Applejack, who had started paying attention after the plate had shattered. "You used a memory exchanging charm to get over here yourself. Couldn't you use the same thing to get us back?"
"And put us where?" asked Rarity. "Our doubles? Twilight admitted she's never met us before."
"How about the first six Ponyvillians we come across?" said Rainbow Dash jokingly.
Rarity failed to find the humor, and she stood aghast. "Absolutely not!" she screamed. "Am I the only pony here with morals?"
"Besides, then we'd have six strange ponies running around in our bodies," added Pinkie Pie.
"Actually, we can avoid that part," Twilight corrected. "It's theoretically possible to make the transfer spell one way. We'd be both here and there. The original owners of the bodies would just sort of disappear."
Rarity's jaw hung a good foot below her face. Pinkie Pie's literally hit the floor.
"And that would be wrong," added Twilight quickly.
"There is another way," said Doctor, desperate to move the conversation in a direction away from body snatching. All of the other ponies turned to look at him. "If increasing the force won't help us, we can instead weaken the boundry between worlds."
"That's what I've been trying to do," complained Twilight. "I've mapped out the strength of the wall, and it's thinner in the Everfree Forest than anywhere else. That's why I sent the other Twilight there to perform the transfer. I even made your Zecora move there to help facilitate the experiments on the other end."
"Zecora helped you kidnap Twilight?" asked Rainbow Dash, horrified.
"No. Your Zecora stopped helping me after..." Twilight trailed off, again trapped in the memory of the exploding pegasus. It was worse now, because Twilight knew it was her fault for not stopping to think about what she was doing. She had never considered that it was the journey itself that had caused the accident, rather than getting stuck halfway.
"I mean weaken the boundary artificially," said the Doctor trying to keep the conversation going.
"Like a rock through a window," Twilight said softly.
"Exactly! Like a rock through a window!" The Doctor pumped a hoof triumphantly, then turned to Twilight mystified. "I have no idea what that means."
"Yesterday, I said that the barrier between worlds was like a pond." Twilight smiled as she spoke, a glimmer of newfound hope in her eyes. "Magic passes through it really easily. But it's only a pond for magic or energy, and it becomes a wall when you try to send matter through. But remember what happened to the rock I used in the example? It sunk. It passed through. No, better than a rock, a book." She levitated a book off of one of the shelves and opened it, tearing out two pages.
Rarity gasped, and Twilight shifted her eyes toward her, concerned. "What?" Twilight said. "The book's already in terrible condition. It looks ancient. Really, how valuable can a book like that be?"
Rainbow Dash facehoofed for a second time.
"Now watch," said Twilight, making sure she had everypony's attention. She placed one of the pages on top of the book, the other page hovering beside it. Then she dispelled the levitation. While the book and its accompanying page dropped to the floor quickly, the lone page fluttered slowly to the ground.
"It's a nice little science experiment," said Applejack. "But would you mind tellin' us what it means?"
Twilight grunted, irritated that the other ponies couldn't grasp at the metaphors she was trying to make. "The page fell quickly because it had no air resistance. It moved faster than normal because of the book. Alternatively, think about if I had tied a message to the rock before I threw it? The point is, instead of using magic to try and push us through, we can ride behind it, like a vehicle. I said that using magic causes ripples, distortions in reality that make our worlds different. If we can make a ripple intentionally, big enough and precisely calculated, we can make it break down the wall for us, and we slip through in its wake."
The Doctor nodded, in thought. "That's the principle, yes. But you need to be careful when you're messing with the fabric of reality. If you let things get out of hand, boom!" and he threw his hooves upward, miming an explosion. "Vortex."
"What exactly is a vortex?" asked Rainbow Dash.
The Doctor hummed and waved his hooves around sporadically as he tried to come up with an answer. "It's kind of like a black hole," he said at last.
Rainbow looked at the Doctor blankly.
"A black hole?" said Pinkie Pie, excited. "Mrs. Cake said I have one of those for a stomach."
Applejack rolled her eyes. "Here's an idea," she suggested. "Let's not have to find out what one of those vortex-majiggers is."
Twilight nodded. "Agreed. But how do you carefully create an explosion?"
Rainbow smiled and rubbed her front hooves together. "This ought to be good," she muttered excitedly, a lifelong fan of blowing things up.