Before the contradiction between light and dark was a metaphor, it was a fact.

All metaphors are the shadows of facts. But when you clear away the shadows, what comes is not the clarity of light. Because something was causing the shadow, and you got rid of it.

Whoops….

---

Twilight Sparkle’s first choice wasn’t a matter of great significance. Her mother had dangled a pair of jangly objects over her crib, and Twilight had reached for one.

She hadn’t gotten it. Her mother had been looking away and just kept shaking them. But even then, Twilight was a pony who knew what she wanted.

Twilight was a frustrated baby. Everypony commented on how cute she was to her parents, but they did so with a stretched smile, for Twilight was quite an ugly baby. She was too fat in some places and not fat enough in others. Her mane sat wrong on her head, like a giant feather sticking out of a tiny hat. And there was something unnerving about her eyes. They made ponies feel sized-up, even judged, by a gurgling purple pile of fat and hair.

Her mother said to her father once, “There’s something not quite right about Twilight. She stares at me. I know she’s too young to, you know, think. But I can’t help but feel that she is staring.”

“Foals stare,” her father had suggested.

“Not with intent,” her mother said. She had always wanted three foals. Twilight was her first, and she would be her last. Even two of them staring at her like Twilight did would be too much.

Her parents felt outmatched for Twilight as she grew into a filly, like a well-meaning couple whose foal had been swapped out for a baby alligator in the hospital. Twilight was not a rebellious child. But her body grew out of one awkward phase and into another. Just as her hair started to sit right on her head, her knees began sticking out at jarring angles. She was more cube than pony when she walked—she called herself Cubit for nearly six months and wouldn’t answer to anything else.

Feeding Twilight was always frustrating. She never ate carrots until one day she did, only to abandon hay the very next day. She developed heretofore unnoticed allergies that were gone in twenty-four hours, and she seemed to be susceptible to catching a cold on a moment’s notice, whereupon she would insist on drinking hot apple tea for dinner and nothing else, regardless of whether they had any. One day Twilight’s mother gave up and bought a big box of tea bags to keep in the pantry. Twilight’s condition never came up again, and when she did catch a cold once a year or so, she ate soup and pudding quite reasonably.

Twilight had too many interests. She took notes on everything. She was obsessed with taking notes. She tallied how many hours she slept, what she ate and the number of bites it took to eat it, where she sat and for how long. She counted the words ponies spoke and broke them down into letters and syllables and then wrote up an advisory note for her parents telling them helpful ways to change their speech patterns to use more vowels and fewer consonants. Consonants, Twilight argued, were a stress on the tongue and lips, and doctors didn’t tell you this because they were after your money. (To say that Twilight hated going to the doctor would be like saying Nightmare Moon hated Princess Celestia—accurate, but frightfully insufficient.)

The only peace Twilight’s parents could ever get in the house was when Twilight was reading at the library. Fortunately, she was at the library a lot, and they encouraged her to spend as much time there as possible by getting her a library card and letting her check out anything she wanted. The librarian soon became fond of the awkward, jerky lavender Unicorn who would spend entire days sitting at a table in the far corner with a pile of books and a small bag of apple slices. After she tried engaging the filly in conversation, this impression quickly flipped: Twilight was arrogant, ungrateful, had seemingly no control over the decibel level of her voice, and would ask a question and then run on through with some tangent without pausing for a response, or indeed, breath.

She was also distressingly nervous. The librarian found it uncomfortable to watch her up close, all jerks and tics—her ear would twitch one way while her tail swished the other, and her mouth would spill over with words as she rushed to correct whatever imperceptible error she seemed to think somepony else would detect in her. The librarian suspected abuse at one point, but the fear that she might be asked to take in Twilight for a while stayed her from any investigation. It was cruel and selfish, perhaps, but few could take those eyes that bored into your soul and then still worry what that filly did to herself when she looked in a mirror.

Twilight eventually grew into her body, like her alien brain was finally learning how to wear its horse shell. Her proportions evened out, her hair started to make sense on her head. If she still talked too fast, at least she was coherent: The traffic jams of speech that got stuck in her mouth until they built up and overflowed were getting rarer and rarer.

But while her brain was learning to be a pony, the ponies around Twilight were finding it harder to accept Twilight’s brain. The way her eyes diced you up and valued your parts, the way she moved from warm to cold when she wanted something from you or didn’t—her personality was like that one week when Princess Celestia had the flu and kept jerking the sun around every time she sneezed—her arrogance, and even more grating, her power and genius to back up every brag, or maybe she thought of her bragging as honesty, which really grated....

It wasn’t a mystery why she didn’t have any friends, a fact that Twilight’s parents had twice been called to the school to discuss with Twilight’s teacher and the principal. It was a mystery why they hadn’t all ganged up and killed her.

So Twilight’s acceptance to Princess Celestia’s School for Gifted Unicorns came as a relief to her parents. It was a boarding school. Year round. They were very proud, of course. Very proud. The full scholarship helped.

And Twilight was very excited, spilling over with joy, and at the same time more seized with worry than ever. She insisted on reading in the bath now, using magic to keep the book out of water. Twilight’s mother had never seen Twilight endanger a book before—she had seen Twilight trip once while reading and walking at the same time, and rather than land on the book, Twilight had twisted over so that her body protected the volume from damage. But Twilight said reading in the bath gave her motivation to get stronger to ensure the safety of the book. And she did not get so much as a single soap bubble on any of her books.

So Twilight would be going, which was wonderful for her parents—wonderful that she was going to get an excellent education, of course. And they would be very sad when she left, for she would be staying at the school in Canterlot except on holidays.

Twilight’s application had been accepted at the end of the spring semester. A long summer stretched ahead. It now included a baby dragon. They hadn’t been expecting that. A pony from the palace had come with special instructions about it, and Twilight was taking responsibility, which meant that there was now always a fire-snorting lizard perched on her back while she went about her unpredictable routine. But there was light at the end of the tunnel.

At least Twilight was spending most of her time at the library.

---

If her parents expected Twilight to not fit in at her new school for gifted Unicorns, they were wrong. Or at least, they were right for the wrong reasons.

For most fillies and colts, their first and most traumatizing experience at Princess Celestia’s school was the realization that they were no longer the top of the class. Instead of effortlessly being the smartest pony in their entire school, it now took real work just to keep up with everypony else.

But one pony still had to be the best, and that pony was Twilight. She was effortlessly at the top of her class, although she worked hard, just on her own projects. She invented a new language and wrote an essay in it. She spent an entire day using only three legs to walk. She practiced teleportation spells until her classmates complained that the constant flashes of lavender light gave them headaches.

If anything, though, Twilight was less sure of herself than before. Her arrogance was checked, but not by the company of fillies and colts nearly as smart as she was. Only one thing could distract Twilight from her latest obsession or game at school, and it was not her peers or teachers.

Some of the fillies began to notice the way Twilight’s head snapped around whenever Princess Celestia walked by. Princess Celestia didn’t run the school in an active way, but she was around often enough, walking through the halls and smiling at fillies, occasionally talking to one, asking if they were enjoying their classes and making sure the students felt comfortable letting her know if they thought a basilisk was creeping around in the school pipes or if one of their teachers was a werewolf.

It seemed to them like Twilight was avoiding Princess Celestia. She shrank back in the hallways behind others lest she be addressed by the princess. She didn’t volunteer to be one of the presenters for a class project to the princess at the end of the semester.

But Twilight would stare at the princess when she was around, and then she would go to her dorm in the evening and look at herself in the mirror. It was starting to have a strange effect on the filly.

“I can’t talk to her until I’ve read this difficult book,” she would tell herself. And then she would read it. “I’ll have nothing at all to say to her until I master this advanced spell.” And mastered it soon was. But each peak she climbed only lifted her above the fog to see another. She might as well have been running toward infinity.

---

Simple Pleasure beamed at the fresh new crop of Gifted Unicorns. Every year, she took the new class on a tour of the One Bank at the end of their first semester. This year they were going to see the Gold Room.

It had taken years to get approval to visit the Gold Room. Usually the tour stuck to the approved parts of the Bank: the entrance, the exit, and the gift shop. Admittedly, the gift shop was pretty great. You got to spend fake money and experience inflation and deflation in real time. The artificial economy took you through speculative booms, spectacular busts, and then it gave the visitors control of the artificial money supply to try to get the economy on track. Simple Pleasure let the fillies take turns being central bankers. Every year somepony went for pure destruction, and the chaos was always glorious to behold, especially when some of the other fillies were bright enough to pool their resources and fight back.

“Can I have your attention, everypony!” she said. It took several more iterations for everypony to quiet down. Getting a group of restless children to be quiet was a matter of finding something else to hold their attention. For Gifted children, it was as simple as asking a question.

“Can anypony tell me when the Bank was first established?” she asked.

“One thousand, four hundred and eighty-six years ago,” a filly immediately answered.

“Very good!” said Simple Pleasure, putting a note of surprise into her voice. “I’d forgotten this was a class of Gifted Unicorns.”

This earned quite a lot of pleased laughter. Simple Pleasure knew that many of these fillies were here because they didn’t fit anywhere else. Too smart, too weird, too reclusive, and often too dedicated to peculiar interests to form bonds with the other ponies their own age or even with their own parents and siblings. Princess Celestia seemed determined to find and gather not simply the best Unicorns but the ones who were struggling to find their place. Undervalued, that was the word, it was how an economist sought out opportunities.

After a tour, there were always one or two fillies who came up and spoke to her. They thanked her for being an adult who treated them, not like they were normal, because they didn’t want that, but like they were...natural. Like nothing had gone wrong for them to be the way they were. Like they could be accepted, like how a family was supposed to. Unconditional love—most of these fillies had good parents, but that didn’t mean unconditional liking, or unconditional knowing-how-to-deal-with-a-filly-who-could-read-and-add-numbers-before-she-could-talk. She knew that the senior cohorts ended up calling themselves Sisters, the few who could make it to the very end of Princess Celestia’s training, anyway.

Most wouldn’t and weren’t meant to. The division of labor didn’t require everypony to become an elite economist. Still, she had fun picking out the ones she thought would make it all the way as they walked toward the Bank.

They turned left, and the Bank loomed over them. It was not an especially large building, although it stood out over the bookshops and cute little coffee-study dens that populated the area around the school. But the Bank loomed. It had weight, like gravity, that drew your eyes to it. Simple Pleasure had to stop herself from walking faster, and from a sudden commotion behind her she knew fillies had bumped into each other.

“Take care to walk slowly,” she called out, turning around to make sure no pony was hurt as the confused children sorted themselves out. “The Bank can pull you forward if you’re not prepared.”

Some of the fillies looked uncertain, others intrigued. For most of them, this would be their first experience with Princess Celestia’s peculiar brand of magic. It wasn’t just stronger; Princess Celestia had access to whole categories of magic that most Unicorns would never explore.

“Does anypony know why the Bank is so heavy?” she asked once it seemed like the fillies had mostly gotten used to walking near the Bank.

A lavender Unicorn spoke up. “Because the Bank has the Numeraire in the very center.”

“But why does that make it heavy?”

“Because the Numeraire weighs One. No matter how much you take out of it, it still always weighs One, but it erodes, and all the little pieces weigh something too, and they add up to make a bigger One. Princess Celestia has it in a chamber that’s nearly a vacuum, but it’s still had over a thousand years to build up dust.”

“But that doesn’t have any effect on the economy, surely.”

“Actually, it causes inflation because it keeps taking more bits to add up to One. It’s about two percent inflation per year.”

“Then why doesn’t Princess Celestia clean out its chamber?”

“Because outside of the chamber the dust might form a second Numeraire, and then you’d have two units of account. You’d get two different prices every time you went shopping.”

Simple Pleasure was impressed. Now she wanted to keep pushing. “So what happens when the Numeraire completely erodes?”

“It’s only theoretical,” said the lavender Unicorn, completely undeterred, “but it’s called the heat death of the economy. Simply put, value won’t have any meaning. But we’re a long way from that.”

“That’s right,” said Simple Pleasure, making a mental note. The lavender Unicorn moved like she hadn’t mastered walking even before they had gotten near the Bank. Yet she was also levitating a small rock along the street as they went, knocking it against the ground in a way that was as smooth and natural as her physical movements weren’t. She was odd, but Simple Pleasure had already moved her to the top of her mental Going To Make It list.

She also made a mental note of the murmur and soft laughter in another part of the clump of fillies. No surprise there. Even among the best and brightest, there was still a best and the brightest. She looked at the filly at the center of the noise, a Unicorn with a coat so bright pink and glossy it almost looked like the candy coating that would go around a piece of chocolate. The filly beamed back at her with a face of perfect innocence. It was so convincing that Simple Pleasure doubted herself. Maybe they had been laughing at something else.

The doors of the Bank were made of glass, which was meant to signify transparency—ironic, considering most of the Bank was walled off by magic, as well as by mundane physical locks and barriers. Princess Celestia’s philosophy was that expectations mattered more than reality. It was also her philosophy, according to rumor, that eating an entire cake at three a.m. was a perfectly reasonable thing to do.

“Slowly, slowly!” she urged as the fillies started coming in. They squawked or jumped as they moved into the entrance lobby, their hair sticking out and their horns sparking. There was so much atmospheric magic in the One Bank, even in the front lobby, that sensitive Unicorns often reacted this way. The lavender filly was chattering and rocking back and forth on her heels.

Simple Pleasure gave them a few minutes to adjust to the Bank while she made conversation with the receptionist at the front desk, Pocket Protector, who had become an aunt only last week.

Twilight Sparkle was grateful to have some time to explore by herself. She loved museums and historical sites but hated tours. The guides always knew less than she did.

But even she didn’t know much about the One Bank. There wasn’t much to know, or rather, there wasn’t much that Princess Celestia was willing to say. So Twilight looked around eagerly, her eyes wide to expand her peripheral vision and her eyebrows raised to maximize creative thinking. Was it likely that the lobby of the Bank held a clue to its deeper mysteries? Probably not. But there was a chance, and she was going to make sure that chance was hers.

The front desk was made of white marble and had a very classical look to it, as did the Ionic columns. A few royal guards in gold armor stood stiffly by the doors, holding ceremonial spears that would have done about as much against a real threat to the Bank as actual toothpicks.

But what caught Twilight’s eye was the map. It was in an awkward spot, partially hidden by the front desk and one of the columns so that you had to look down from the high ceiling with its elaborate gilded patterns and away from the rare paintings on the walls to spot it. And it wasn’t like there was any pathfinding to do in the Bank; anypony who wanted an adventure was sure to get one, one way or another.

But Twilight went over to the map anyway. It seemed a little too inconspicuous in this vast space of gold and marble and other ostentatious displays of old grandeur. The map was kind of like a subway station map, with an arrow pointing to the lobby saying You Are Here. The gift shop and the exit were helpfully marked as well. Nothing else was. And yet it was full of detail. Rooms were displayed as small colored shapes on a flat circular plane with passageways shown as gold lines running criss-cross between them. At the center of the circle everything seemed to flip over, and for a minute Twilight thought the two halves were symmetric. But as she studied the map intensely, she noticed small incongruities. There were more and more of them the more she looked, until she couldn’t even remember why she had thought the two halves of the circle had anything in common.

The glass covering the map was fogging up. Twilight realized her snout was pressed up against it and pulled back. Now she could see why she’d thought of the circle as being made of two halves: the entrance was at one end, the exit was at another, and there was a straight line between them that went through the circle’s focus.

The gift shop was a one-minute walk from the lobby.

The absurdity of it overwhelmed Twilight. The map made no sense. It was as if it existed to taunt them with just how little of the Bank they were actually going to see.

She peered at the map again. Was her mind playing tricks on her? The incongruities weren’t the same incongruities as last time….

Needing resolution, Twilight cast a light from her horn, the same she would use to find something that had fallen and rolled underneath her bed. But as soon as her magic touched the map, the passageways between the rooms lit up, and everything started to move. The rooms drifted along the golden paths like stars in orbit. Only the center remained constant. Twilight wondered if it was supposed to represent dead water.

“Hey!” said a voice. “Look what Twilight did!”

Twilight looked up guiltily. Of course it had to be Candy Coating.

The glossy pink filly was grinning. “Ms. Tour Guide, Twilight’s touching something she’s not supposed to!”

Twilight’s heart jumped, but Simple Pleasure was unbothered. “That’s just the map of the Bank, fillies. You’re allowed to look at it.”

Candy Coating instantly switched tactics. “Wow, great find, Twilight! Come on, let’s see what Twilight found.”

Candy Coating’s entire group of friends followed her like bees to their queen and circled around the map, butting Twilight out. Twilight couldn’t help but roll her eyes at the use of physical force. In the company of magically prodigious Unicorns, the biggest filly was hardly the most threatening. Indeed, Candy Coating had a slight frame. It was her instinct for social weaknesses that made her powerful. For Twilight, “social weakness” was a tautology.

She had learned to brush off Candy Coating’s taunts and cruel little games. She had taken a look at her, after all, and seen nothing there. That was why Candy Coating hated her so much.

“You think you’re smarter than me, don’t you?” Candy Coating had said furiously at the end of the first week of school. The pecking order, although not fully sorted out, had already established Twilight firmly at the top by that point.

“I, yeah, I guess so,” Twilight shrugged helplessly. They both knew it.

Their first clash had been over monetary policy. It hadn’t been anything important, just a classroom discussion about how to define quantities of money in various circumstances. The argument had gone Twilight’s way, which made her feel bad afterward reflecting on the debate in her room—there was nothing Candy Coating could do, Twilight had read more and thought faster, she could have won from any position—but Candy Coating’s pride had been wounded.

“My sister is a Sister,” Candy Coating had said as the ultimate trump card. “She’s going to graduate and work for Princess Celestia, and I’m just saying what she said. You don’t think you know more than a Sister, do you, Twilight? No, you’re too good to be a Sister, aren’t you? You think you’re better than everypony.”

Twilight didn’t know what she had done to give that impression, so she stayed silent. Apparently it was true: Candy Coating’s sister really was a Sister, a member of one of the elite cohorts in Princess Celestia’s economics graduate classes. Sometimes the cohorts were as small as ten mares, and some years no pony graduated at all. Candy Coating used that borrowed status like a cudgel, beating down challengers and forcing others into her social orbit, which was unusual for her. Usually she worked like a surgeon with a scalpel, but her sister was a big red button, and Twilight had inadvertently pushed it.

“I hope you make it,” Candy Coating had said with narrowed eyes after Twilight confessed her intellectual superiority. “I hope you become a Sister. Because I’m going to be a Sister, and when I am I’ll get to do whatever I want to you. You better drop out now, Twilight. It’s only going to get worse for you. I guarantee it.”

It all bounced off of Twilight. It wasn’t like she expected to make friends. She didn’t see what friends were for. You could talk to them, but most ponies were boring. Books said things too and were more interesting. You could play with models. Equations were toys you could take anywhere and never had to clean up.

Seriously, what were friends for? How many other social institutions were obviated by libraries? Aside from schools. Actually, what were schools for?

But for once, Candy Coating was getting to her. Twilight wanted to see the map. She had barely gotten a moment to study it. And now they were keeping her out. What was she going to do, toss one of them aside with magic? She’d get in trouble and not get to explore the Gold Room.

And she very much wanted to see the Gold Room. According to what she’d read, it was the room where Princess Celestia worked her greatest magics. Being inside the Gold Room would be as close as she could get to being inside the mind of the princess herself.

It was also said to be full of so much gold that trying to look at it was as blinding as staring at the sun. This rumor, according to what she’d read, had inspired some very stupid and short-lived thieves. Greed was the ultimate motivator, Twilight reflected, if it could make somepony try to take on the Bank.

Candy Coating and her lackeys were bored of the map now that they had taken it from Twilight. They wandered away, but before Twilight could look at it again, Simple Pleasure clapped for their attention “Are you all steady on your hooves? It’s time to visit the Gold Room. Follow me and do not stray I will be watching yes that means you Ms-Thinks-She-Can-Wander-Off.”

They were lined up into two columns and followed Simple Pleasure down a corridor. A minute later, a guard in shiny gold armor and a shiny gold helmet stopped them at the door to the Gold Room. He produced an oversized gold key and inserted it into the lock. It didn’t open. Instead the number 2 indented into the door.

“Uh,” said the guard, but professionally, so that you knew he still had things under control. He tried the key again, but nothing changed.

“Does it usually do this?” Simple Pleasure asked while the guard continued to fiddle with the lock.

“Lady, I’ve been a guard for my whole life. In all my time I’ve only seen three doors open in here: the entrance, the exit, and the gift shop. My father was a guard his whole life, and he only ever saw three doors open. His father was a guard his whole life, and he only ever saw three doors open.”

“Were you given any instructions?”

“Don’t lose the key.”

Just as he tried turning the key again, it snapped in half. He reared back in fright as the lock opened up like a mouth and chomped the broken-off half of the key to bits. Twilight winced at the metallic crunching noise. It sounded like Spike when he was eating rocks.

“Don’t panic!” Simple Pleasure said, which is never the right thing to say inside a bank, or Bank. Fillies started speculating all at once.

“I heard that if you go into a part of the Bank you’re not supposed to, a monster will eat you,” said a green filly with a spying-glass cutie mark.

“Princess Celestia could do much worse than that,” Twilight said mildly. Her calm tone had the effect of drawing the attention of everypony there. “Look at the number on the door. Maybe it’s a clue, like you’re supposed to feed two keys to the door.”

“I only had the one,” said the guard, who clutched onto Twilight’s words like a drowning pony to a thin branch in a raging river. If he had lost a key of Princess Celestia’s—a key to a room in the Bank—then he was fired if he was lucky. He was dead if he was lucky. There were rumors about the Bank. His father said his father said his father said he had been told dragons had tried, centuries ago, to melt the bank with fire so hot it would blacken a pony’s coat from a mile away. But—so his great-grandfather had been told—all they got for it was an eruption of molten gold that melted them, and now their bones were inside the Bank and made it stronger.

“Well, let’s try something else,” Twilight continued, unbothered. “What else could ‘2’ refer to?”

They all stared at her.

“What?” said Twilight. “We’re trying to get into the Gold Room.”

“I-I’m not sure that we are….” Simple Pleasure trailed off. She was staring at the broken key with a stunned expression on her face.

But Candy Coating was sure. “We’re not allowed,” she snarled at Twilight. “That’s why the key broke.”

“If I wanted a bunch of smart Unicorns to try to get into a locked room in the Bank, I don’t know that I would give them permission and a big golden key, then have the door eat the key and a big number ‘2’ appear on the door, but having seen it, I have to respect the technique,” said Twilight. “Of course we’re supposed to get into the Gold Room.”

“Don’t you know anything about the Bank?” Candy Coating said. “Only Princess Celestia is allowed in.”

“I think that’s up to Princess Celestia,” Twilight said. She glanced at the 2 again. “Maybe you’re supposed to go in as pairs, like she might have done with Princess Luna long ago.”

“None of us are going to go in with you!” said Candy Coating. She was furious, and Twilight didn’t understand why. “You’re not a Sister, Twilight, so shut up about the Bank! You don’t know everything!”

Before Twilight could think of how to respond, another filly interrupted. “I’d like to see what’s behind this door,” said Twinkleshine. “Not because I care about the Gold Room. But adults always try to hide things.”

This sent ripples through the class of Unicorns. Even Twilight, who had as much grasp of social dynamics as the average pony has of fluid dynamics, sensed how momentous this moment was.

Twinkleshine was talking to somepony.

If Twilight was top of the class at academics and Candy Coating was queen bee of the social hive, then Twinkleshine was like a cloud passing high overhead: untouchable, but good for gazing at. Because Twinkleshine was pretty. Really, really pretty. Even Twilight could tell how pretty Twinkleshine was, and Twilight was the sort of pony who’d written a letter to the administration at the start of the year suggesting that the school uniform be gray overalls because they were easy to clean and functional in a variety of situations.

Twinkleshine hadn’t said a word to anypony since joining their class three weeks after the start of the semester. Her dad was a very wealthy businesspony, and there were rumors that he’d gotten Twinkleshine into the school with a large donation after she’d failed the entrance exam. Whatever the truth was, few ponies had approached Twinkleshine, and Twinkleshine hadn’t tried to make friends. She always sat in the back corner of the classroom, looking out of the window at the sky, and ate lunch alone. But as far as Twilight was aware, Twinkleshine was getting good grades, and she never looked stressed when the teacher called on her for an answer.

While the rest of the fillies processed the shock of what was happening, Twinkleshine walked around to where Twilight was standing, frowning at the door with an intense look of concentration. “Two keys is silly unless each key has to be found in turn, and then you might as well lock one key behind two tests. As for going in together, Princess Celestia and Princess Luna were said to have traded off duties between day and night. They didn’t go in together except for very momentous occasions.”

Twinkleshine’s face was too serious for her young age as she studied the door. Oh, thought Twilight vaguely. Is this what other ponies see when they look at me?

She’d never wondered that about anypony before.

“Yeah,” said Twilight. “Those weren’t good ideas, just my first ideas.”

“Those were good first ideas,” disagreed Twinkleshine. “As you can see, most ponies’ first ideas are to panic and to freeze. A lot of commotion, but no motion.” She grinned at Twilight, whose brain felt utterly confused. But her face figured it out, grinning back without any conscious input on her part.

“So what could the ‘2’ mean?” Twilight asked, still unsure of how to process the giddy sensation that seemed to be making her cheek muscles stretch. “I can’t think of anything that you need two of to go through a door.”

“Two forms of identification? Banks always require that.” Twinkleshine’s smile was wry, to show the suggestion wasn’t serious. “When adults want to hide things from fillies, they just put it in plain sight and don’t say what it is. What the ‘2’ is is right in front of us, one way or another. I’m sure of it.”

The shock of seeing Twinkleshine reach out to somepony seemed to counterbalance the shock of the door eating the gold key. Now other ponies were warming up the idea of using their intellect to get into the Gold Room. Muttered suggestions were offered up as a conversation began to flow. “Maybe there are two doors, and this is the second one,” said a blue filly with an hourglass cutie mark and a mane like a swoosh of toothpaste.

“Maybe,” Twilight said, “but by that reasoning there could be a dozen doors.”

“It depends if the game is fair or not,” said the blue filly’s companion. Twilight recognized this one as Lemon Hearts, who was infamous for getting her head stuck in a beaker on the first day of class.

But the suggestion was good, and Twilight regretted being quick to judge Lemon Hearts. “Are there other entrances to the Gold Room than this one?” She directed this question to Simple Pleasure and the guard.

They didn’t know, so Twilight moved on. “Two could mean a lot of things. Is there anything you were told about the key or the door? Something we should know?”

The guard concentrated like his career depended on it. “Don’t lose it,” he finally said.

“You’ve already done that. I like the door idea. Does anypony have any other suggestions?”

“Prime numbers?” a filly suggested, but Twilight didn’t know what to do with that, and neither did the blue filly, who introduced herself as Minuette.

“There’s a map by the lobby,” Twilight said. “Let’s go find another door.”

---

The lobby receptionist made a consternated face as a rush of excited schoolfillies piled out of a corridor and swarmed the map. Simple Pleasure and the guard followed behind with nervous expressions. Twilight touched the map with a lavender spark from her horn, and it lit up and began to move again, the rooms orbiting slowly around the unmoving center.

“This is the entrance,” explained Twilight, pointing, “and this is the exit. See how it bisects the Bank?”

“Where’s the Gold Room?” Twinkleshine asked.

It took Twilight a minute to locate a room that corresponded to the path they’d taken in the corridor. “Right here,” she said, pointing at a room immediately west of the immobile centerpoint. The Gold Room wasn’t moving either, or else it was moving very slowly.

Minuette and Lemon Hearts squeezed around to see. “There’s only one golden passageway running into it,” said Lemon Hearts, crestfallen. “I guess that means there’s only one door.”

“Or there’s a second door to a second room,” said Twilight. She was looking at a room that was also right next to the centerpoint but on the opposite side of the Gold Room. “Maybe there are two Gold Rooms, or the Gold Room is the second part of a pair.”

Twinkleshine had been studying the orbits with an intense look. “Okay, is it just me, or does the motion of the rooms not make total sense? Look, when one of them crosses over the line determined by the entrance and exit, it, like, loses a step, or something.”

“It looks like it loses a beat to me,” Minuette said.

“What do you mean?”

“Well, I never took music lessons, but when I was really little my mom would play the piano, and I would sit on her lap and read the sheet music. You can change how a piece sounds by, I don’t know the terminology, but by slipping or shifting a beat, you can make any piece sound jazzy or waltzy or anything. It looks to me like there’s two different dances on two different sides of the Bank.” She demonstrated by whistling a tune, shifting down a beat, then back up.

“But if you watch how it comes back around, it doesn’t end up where it originally was on the first half of the Bank,” said Twinkleshine in frustration.

“You can’t necessarily cut a beat and then add a beat back in,” said Minuette. “Because, um….” She paused for a moment, looking for words. “If you have a pizza with spicy peppers, and you take the spicy peppers off for somepony who doesn’t like spicy food, you can’t look at the resulting cheese pizza and know that spicy peppers were the specific topping taken off.”

“So why does this room end up here?” demanded Twinkleshine.

“It’s guessing?” Minuette shrugged.

“Guessing is fine,” said Twilight vaguely, her thoughts suddenly very abstract. “Sometimes you have two mathematical structures that don’t, uh, entirely ‘know’ each other, but they’re trying to figure each other out….”

Lemon Hearts rubbed her eyes. “Looking at this is making me dizzy. What’s the point of the two halves anyway?”

That was a good question. Now that she knew about the guessing, the flow of the rooms into and out of the two halves looked so natural that Twilight hadn’t thought to ask why it was happening in the first place.

They stared at the map together. Finally Twinkleshine said what they all were thinking: “Either she couldn’t make up her mind as to what she wanted, or she had to compromise. Why would Princess Celestia have to compromise?”

A fifth filly spoke. “I mean, it’s probably to do with Nightmare Moon. Obviously.”

They looked at her. She was Moondancer, if Twilight remembered correctly. Moondancer had a distinctive mane, red with twin stripes of different shades of purple, like a national flag designed with the only colors left in a well-used box of crayons. She wore thick glasses and her tail needed to be combed, but the most notable thing about her was that she was always reading, always.

But now she had put her book in her bag. Twilight had never seen her complete face before. Moondancer was squinting, like there was too much light hitting her face at once.

“Princess Celestia didn’t build the Bank on her own,” Moondancer continued. “I was just reading about it in Ae Hiftorie of the Newe Bank. They don’t talk about it now, but Princess Luna didn’t merely take over the Bank’s duties at night. She built half of it, and half of it was hers.”

She pushed through their group to point directly at the map. “The two sides of the Bank were meant to be in communication as long as the princesses were. So I can only make sense of this one way. The Bank is actually moving.”

They all paused as if to listen for the sound of mysterious rooms sliding along unseen tracks.

“Except for this part,” Twinkleshine indicated the center. “And if the Gold Room is moving, it’s too slow to see.”

“But that’s just it,” said Twilight excitedly. She’d made a connection; something that had been bothering her previously now slotted neatly into the conceptual space that Moondancer had opened up. “See on the other side of the center? There’s a room parallel to the Gold Room.”

“...The Silver Room?’ said Twinkleshine in disbelief. Her mouth was open as she looked at Twilight.

“It might be!” Twilight answered. Her mind was racing now. Everything felt true, even if she didn’t know how to prove it. “How do the rooms know which side of the Bank they’re on? It would have to be by proximity to the Gold Room or the Silver Room. That would tell them whether they’re in the orbit that Princess Celestia chose or the one made by Princess Luna.” Her mind made a further connection: “The Gold Room really is like the Sun; if you’re on the same side as it, then you’re on the Day side of the Earth. And the Silver Room is like the Moon: If you can see it, you know it’s Night. And then this thing in the center here, I thought it was dead water, but it’s actually the Earth, which doesn’t move because it’s the origin that everything else revolves around. So in the morning, there would be one version of the Bank that Princess Celestia used, and at night Princess Luna would open up a different Bank in this same space….” She trailed off, wondering just how that was possible.

“So a Day side and a Night side of the Bank,” said Minuette. “Like using a key change in a musical piece to evoke the rising or setting of the sun.”

“It’s a key change, all right,” said Lemon Hearts eagerly. “I bet there’s a Gold Key for the Gold room and a Silver Key for the Silver Room.”

“And the Earth in the center,” said Twinkleshine in a low voice. “Pulling in everything around it. That must be where the Numeraire is. The Gold Room and Silver Room are where the princesses do magic because of the proximity to the Numeraire. I told you it was hidden in plain sight!”

“Yeah,” said Twilight, trying to control her breathing. She could feel the excitement buzzing around them as their other classmates were starting to see where this was going too. “And the other rooms are like stars and planets and things. You can imagine it, can’t you? Standing in the very center of the Bank, learning about the universe by play of light and shadow, picking out the patterns. One of those patterns would be a golden light filling the room, as if reflected from a room full of gold, and that pattern would be called the Day, and the room would be called the Gold Room—”

“Which we have to get into,” said Twinkleshine, “and can’t because we don’t have the key, because Princess Celestia didn’t give it to us, because she doesn’t actually…oh….”

They all looked at each other in a moment of understanding.

“If I was mad at Princess Celestia,” said Minuette quietly, “I would have stolen her key too. Do you think that if an Alicorn says, ‘stay out of my room!’ maybe the other has to obey that, that maybe the Bank was set up that way?”

Lemon Hearts lowered her voice as well. “Do we know where the real key is?”

“We do,” said Twilight, not whispering quietly enough, still entranced by her new vision of the Bank. “Because the other pattern would be that as light starts falling away, the shadows run up along the eastern wall,” Twilight gulped in breath, “and you would look east and see a light that wasn’t bright enough to notice during the long bright hours called Day, but now is the most brilliant thing in the universe—”

“A silver light,” said Moondancer, “reflected from a room full of silver—”

“Which has the second door!” Twilight said. “No, the first door!”

Simple Pleasure screamed.

“What is it?” said Twilight, shaken. “What’s wrong?”

“Children, you mustn’t—get away from that!” She began to drag them away from the map. “Children, the Bank is very dangerous. We’ll just go to the gift shop, you’ll love the gift shop—do not mess with the Bank, children!”

The five fillies looked at each other. “We weren’t messing, we were playing,” said Twilight honestly.

“Yeah, it was exploring,” said Minuette. “It was fun.”

“Maybe we should listen to the fillies,” the guard said. Generations of his forefathers had faithfully guarded the Bank.^* He was clinging to any hope to not bring shame upon them—and to keep his job. “I mean, they’re pretty smart, aren’t they?”

^* Uselessly. Anything that could threaten the One Bank could flatten a royal guard like a pancake under a steam roller.

“They are children,” snapped Simple Pleasure, “and the Bank is not a toy.”

“Get out of our way,” Twilight said furiously, but Simple Pleasure didn’t budge. The unfairness of it boiled inside of her. Adults always did this. Every time she was making progress on anything real, any time she had an idea she actually cared about, they wanted to take her away from it and make her live in their dull little world where nothing interesting was allowed to happen. And there was never anything she could say to get them to listen; they didn’t think of fillies as real ponies, just cute little imitations….

Because this wasn’t just a test. Twilight was sure of that. Princess Celestia could have played a million different games with them without tempting them to go into unexplored parts of the Bank. So maybe this wasn’t a game at all. Because if Nightmare Moon actually had stolen Princess Celestia’s key to the Gold Room before being banished, and if it really was hidden on the Night side of the Bank, and if Princess Celestia really couldn’t get into that side of the Bank, then no pony had checked on the Numeraire in quite a long time.

The Numeraire was pulling everything toward it, and no pony was sure just how much it weighed.

We have to get that key.

“Get out of the way,” Twilight repeated. There was an edge to her voice.

“Excuse me?” Simple Pleasure snapped.

“If I may,” said a new voice, which projected powerfully through the room like an actor speaking in a play. A filly from their class trotted forward to stand next to Twilight. Her coat was on the darker side of light blue, like a sky that hadn’t made up its mind as to whether to shine or to rain, and her mane and tail were ethereal and silvery like fairy wings. She faced Simple Pleasure with the kind of poise and confidence that Twilight normally reserved for math problems.

“I’m Trixie Lulamoon, pleasure to meet you.” She bowed bizarrely, like introducing herself at the start of a show. “Ma’am, I think we can all agree that we should respect Princess Celestia’s security decisions. I mean, that’s what all of this is about: understanding how Princess Celestia protects our economy. And she’s the one, not, with all due respect, you, who decided to give us that key. She made the map. She made the 2 appear on the door to the Gold Room. She even told us about the orbit of the Sun and Moon around the Earth on our first day of school. I’m not saying we’re going to explore, um, I guess we’re talking about Nightmare Moon’s side of the Bank?” She glanced at Twilight, who nodded. “Of course we’re going to stay away from that. But I think Princess Celestia wanted us to figure this out. I really think she did.

“Yeah,” said Twilight, “so—”

Trixie quickly interrupted her. “I was one of the presenters to Princess Celestia for our end-of-the-semester class project. She told us that being an economist is sometimes like filling in a map of a city with more details so that the map is more accurate. But sometimes, she said, being an economist is like venturing out into new lands with no map at all. You have to make the map. And then sometimes, she told us, it’s like going to a new planet, and you have to figure out what principles of mapping even apply. That, she told me, is what being a real economist is all about. And I’d hate,” she choked up suddenly, “to disappoint her.”

She buried her face in Twilight’s chest, who jerked back in surprise. More astonishing than the contact from a pony she barely knew was the fact that she was trying to reason with an adult, and it looked like it was working.

Trixie clung to her dramatically, but Twilight saw the wink and bit back a grin of her own at the realization.

“Oh—all right,” said Simple Pleasure unhappily. “But we’re going right back to the Gold Room to try whatever ideas you have, and if we can’t get in, then that’s it.”

“Um,” said Twinkleshine. She glanced at Twilight, who had somehow become the leader of the group.

Twilight looked back at her. She knew what the others were thinking. The first door was the door to the Silver Room. That was where they were meant to go.

Then Lemon Hearts did something very brave.

“I know where the key to the Gold Room is,” she said.

Twilight knew too. But there was no way to say it without causing Simple Pleasure to panic.

“Where?” said Simple Pleasure.

“I think Nightmare Moon stole it.”

Simple Pleasure raised her eyebrows in alarm. “How do you know that?”

This was when Lemon Hearts stole the show. She burst out crying. “Because she visited me in my dreams and told me!”

Minuette held the sobbing yellow filly. “It’s true! She told me all about them! It’s why Princess Celestia brought us to the school. It’s so she can keep an eye on Nightmare Moon.”

“Nightmare Moon is locked away in the Moon,” said Simple Pleasure. Twilight was impressed by their performance—Simple Pleasure was arguing with the scenario, rather than dismissing it outright or fighting back on the asymmetric plane of authority.

“But she’s coming back,” said Minuette while Lemon Hearts wailed even louder. “Everypony knows it, the Numeraire is getting heavier, it’s probably sucking her out of the Moon.”

“That’s preposterous!”

“Is it? Is it? What if Nightmare Moon is coming back, and Princess Celestia needs the power of the Bank to stop her! What if she needs the power of the Gold Room, but Nightmare Moon stole the key as a last act of revenge! And she needs us to get into Nightmare Moon’s side of the Bank and retrieve the key!”

“If Princess Celestia can’t do it, why could a group of schoolfillies?” Simple Pleasure shrieked.

“Because the only power that Nightmare Moon wouldn’t even think to guard against is the power of children,” Minuette said triumphantly.

Simple Pleasure wavered—visibly, she was rocking on her hoofs.

“And, and, our friendship is a magic greater than even an Alicorn’s,” Lemon Hearts added.

The walls were cracking. Simple Pleasure was falling, but not yet.

“Maybe the true door to the Bank is inside our hearts,” Trixie said.

“Yeah, and, um, the real keys are the friends we made along the way,” Twilight added.

Moondancer and Twinkleshine looked at each other. They hugged, spontaneously, like the power of friendship had simply compelled them to, irresistible, an attraction beyond even that of the Numeraire.

“If there’s even a whiff of danger,” Simple Pleasure said hoarsely.

“Nothing bad can happen to a group of true friends who are loyal and true,” said Twinkleshine. Lemon Hearts started to snigger, but Minuette clapped a hoof over her mouth.

Simple Pleasure sagged. “Oh, all right. But be very careful.”

“So,” said Twilight. “I think we need to get to Nightmare Moon’s side of the Bank.”

Simple Pleasure spasmed at that, but Trixie was quick to smooth things over. “If it was really dangerous, Princess Celestia wouldn’t have us do it.”

Twilight, who had been asked by the princess to care for a baby dragon, wasn’t entirely sure. Spike tended to breathe fire when he was fitful, and while the flames weren’t especially hot or difficult to dodge, her mane had been singed on more than one occasion.

“How do we get there?” Minuette asked. “No pony has been there in almost a thousand years, presumably.”

Twilight didn’t see how they could figure that out, which suggested there wasn’t much to the puzzle. “It’s going to have something to do with day and night. If Princess Celestia’s entrance is a day entrance, then Nightmare Moon’s entrance is a night entrance.

“Oh! Um,” Moondancer started looking through her book. “Here! It says here that Princess Celestia and Princess Luna—that’s Nightmare Moon—entered where the other left.”

“So the entrance to Nightmare Moon’s side of the Bank is just the exit door?” said Twilight. “I’m not sure that this is even making astronomical sense anymore.”

“Only one way to find out,” said Twinkleshine. Her eyes gleamed. “Want to go open that door with me?”

“Hold on,” Minuette said. “Somepony must have tried to go into the Bank through the exit door before. Like, if you’re leaving, and then you realized you forgot something, would a guard make you go all the way around to the front to get in?”

“Would you?” Twilight asked the guard.

“Of course not,” he said. “Ponies go back in through the exit door all the time. If I’m guarding that side, I’ll just go back in through the exit myself when it’s time to clock out.”

“Maybe it has to be done at night?” Lemon Hearts suggested. Moondancer leafed through her book, frowning.

Concerned they were missing something, Twilight looked at the map again. She realized that she was thinking of the Day side as normal and the Night side as weird. Once she stopped that, they were just two different behaviors. Somehow, the map was translating between them. Strangely, it wasn’t a perfect translation, and yet she couldn’t see how to improve it. Because if you fixed the way the Night moved into Day, then that would change how the Day behaved, and you’d have to rush over to the other side faster than the light did to fix how the Day moved into Night….

Why can’t they just talk to each other? she wondered desperately.

“It’s beautiful,” said Trixie quietly. She was standing very close to her, studying the same map.

“What do you mean?” said Twilight. “It’s terrifying.”

Trixie looked uncomfortable. “They’re doing their best,” she said. “I bet this map has been moving for at least a thousand years. It must have looked very different once, right? And yet I think that somepony from a thousand years ago would see this map today as the same map.” She smiled suddenly. “I’ve got it.”

“Me too,” said Moondancer.

“You go first,” said Trixie.

“The original goal of the Bank wasn’t to maintain a particular supply of bits or a rate of inflation or deflation,” Moondancer explained. Twilight noticed that although she’d flipped to a particular page in her book, she didn’t seem to be relying on it to relay the information she’d read. “It was to maintain a constancy of nominal spending so that what is sold gets bought and what is bought gets sold. See, ponies change what they want and when they want it, and ponies what they want to make and how they want to make it. So even as everything about buying and selling changes, you have to keep the relationship between buying and selling the same.”

“It’s about managing expectations,” said Trixie. “Not our expectations, the Bank’s expectations. See how even though the rooms always end up in different places as a beat gets added or taken away when the centerline is crossed, no two rooms ever bump into each other? Even though everything else may change, and even though something has to change every time a room crosses the centerline, that remains constant.”

“What remains constant?” asked Twilight. “The pattern of orbit translation across the centerline?”

Trixie shook her head. “The mutual consistency of orbits is what remains constant. I don’t think there even is a pattern of orbit translation per se. Instead, there’s a rule defining the relationship between the back-and-forth of day and night, a pattern of structure through the Bank that’s always being preserved.”

“My head hurts,” said Lemon Hearts. Minuette giggled softly.

“But you see it, don’t you?” Trixie insisted. “The night isn’t what happens when the day goes away. It isn’t any time that the Earth is between you and the Sun. In the absence of ponies, there is no night and day, just stuff moving around. Night is what we bring with us from the day so that we can see what’s different when the Sun is on the other side of the Earth.”

“Okay,” said Twilight. Trixie was looking at her like she was desperate for Twilight to get it without being told. The look was so intense that Twilight felt like a need to oblige. “I think I understand. Night is what is consistently different depending on our position relative to the Sun. The things that are the same aren’t worth talking about, and the things that are inconsistently different don’t get identified with our position relative to the Sun. So the night, or Night, is specifically what we observe when we go from day to night, the changes that we consistently notice no matter what else seems to be going on.”

“Yeah,” said Trixie. “Reaching the Night side of the Bank isn’t about going in through the exit. It’s about going through the Bank to the exit. It’s specifically about going from Day to Night.”

Moondancer frowned again at her book. “It doesn’t say that Princess Luna had to walk through the Day side to get to the Night side.”

“Then it’s something mental,” Trixie said. “Or I’m wrong,” she added. Something about the way she said that last part left Twilight feeling certain that Trixie didn’t think she was wrong.

“There’s only one way to find out,” Twinkleshine grinned. “Let’s go to the Night side of the Bank.”

---

As they all headed down the long corridor through the Bank to the exit, Twilight felt a strange bubbly excitement floating her along. It was strange because she didn’t think it was excitement about seeing the Night side of the Bank.

Part of it was that she didn’t actually expect to get into the Night side of the Bank. Princess Celestia would appear in a flash of golden light, congratulate them on getting this far, and deliver a thrilling lecture on the history of the One Bank. The alternative was that Princess Celestia actually needed their help to get into the Night side of the Bank because the Gold Key was there, and she really hadn’t checked on the Numeraire in a thousand years. That thought was a little too terrifying to think.

But the other part of it was these other five ponies trotting along with her at the head of the class. Twilight had been on plenty of intellectual adventures before. But she’d never been on one with anypony else.

She wasn’t the only one feeling it. The other five were exchanging the same glances and smiles that she was. Minuette whistled a jaunty tune as they walked, and Moondancer wasn’t looking at her book at all.

They reached the exit, and the entire class, along with Simple Pleasure and the guard, assembled outside. Blinking in the sunlight, Twilight found it hard to believe that this was the entrance to an alternative nighttime version of the One Bank.

Everypony was looking at her. “Well,” said Twilight after a moment. “I guess there’s one obvious thing to do.” She pulled the exit door open and looked into the Day side of the Bank.

“Yeah, I’ve gone through that door a million times,” the guard said.

“What about at night?” Twinkleshine asked.

“Even then,” he confirmed.

“It’s not about the door,” Trixie said. “It’s about what you bring with you and what you give up.”

“Do you want to try?” said Twilight.

“You’re the smart one,” answered Trixie.

Twilight studied the door. Before they’d left the lobby, she’d examined the map one last time, committing it to memory. Now she had the feeling that the entire map was the Day side of the Bank, and the Night side would look very different.

So….

I’m not leaving and reentering, she told herself. I am coming to this place! I have been to the Day side of the Bank, and now it is time for me to visit the Night side.

Twilight caught herself. Thinking the words in increasingly insistent tones wouldn’t change anything. Instead…it was already true. She had come to the Night entrance. If she opened the door, she would be looking at the Night side of the Bank.

She pulled the door open. There were gasps and a few shouts of terror. The corridor that the open door revealed was not the corridor they had come out of. Twilight got a glimpse of a dark tunnel stretching into shadow, and then Simple Pleasure was in the way.

“Children, do not go in there!” Simple Pleasure stood in front of the door, blocking it. “Well done, Twilight, now we have to call Princess Celestia.”

“We don’t!” They were so close, why didn’t she understand that? Princess Celestia wanted them to do this, she probably couldn’t do this but they could; what Minuette had said was right, it had to be them. Her parents, her teachers, they all did this, they just said things that were stupid because, because they were adults and they just had to.

“Twilight—”

“Get out of the way!” Twilight shouted. “We have to go in there! The princess is counting on us! She needs our help!”

“I think you should listen to the kids,” said the guard, who had never seen anything like this. If the fillies found a key to the Gold Room in there, his rump was saved.

Maybe it was the influence of another adult. Simple Pleasure looked horribly conflicted.

“Fine,” she said, “I will go in alone.”

“No! We have to do it!”

“Then you will come in with me, and we will go together,” Simple Pleasure said. “No pony else can come in.”

“Awww!” said the other fillies. “That’s not fair!” Twinkleshine complained.

“But it’s safe, which is my responsibility,” said Simple Pleasure. “Twilight, stay behind me.”

Twilight followed Simple Pleasure into the Night side of the Bank and was greeted by a blast of cool air. The corridor was very dark. There wasn’t any dust or cobwebs to indicate that it had been abandoned. It was just empty and cold, like something forgotten.

They only had to walk a short while before they saw a small table. On it was a small gold key and an envelope.

The real Gold Key was much smaller than the one the guard had. But while gold was soft and malleable, this looked like iron that had been forged in the heart of the Sun and taken on its color as a result. In the cold emptiness of Nightmare Moon’s side of the Bank, the Gold Key was the only thing warm and bright.

The envelope was plain and unopened and said Celly in neat, careful writing. Twilight took the key, and would have taken the envelope as well. But the instant she touched the key, a force took hold of her body that dragged her toward the door. She resisted until she was pulled off her hoofs and bounced and skidded the rest of the way, landing in a bruised pile outside the Bank. Simple Pleasure ran out after her in alarm, and the door slammed shut.

Twilight was surrounded by fillies. “Are you okay?” “You did it!” “Wow, that key is so pretty!” “What was Nightmare Moon’s side of the Bank like?”

Twinkleshine bullied her way to the front and helped Twilight up. “Lucky,” she sighed. “Still, you’ve got a good head, Twilight.”

Twilight grinned at her. “I just really wanted to be able to go on my class trip to the Gold Room.”

“Now can we call Princess Celestia?” Simple Pleasure asked. “That was very brave of you, Twilight. I’m sure she’ll want to reward you.”

“If she wanted to be here, she’d be here,” Twilight said confidently. “In fact, I bet she’s watching us right now. I think we should visit the Gold Room.”

Now Twilight led the way back to the Day entrance, as she thought of it, and then to the Gold Room. After a pause, she offered the Gold Key to the guard. “Here. So you can do your job.”

“Thank you,” he said, and inserted the key into the lock.

Click.

And they were in.

The Gold Room was pure gold from floor to ceiling. It should have been blinding, but it seemed like the room was lit from within the gold walls and floor. The effect was soft and warm and gave the impression of walking on pure light.

After the initial shock wore off, everypony broke off into small groups to look around, Twilight joined Trixie, Twinkleshine, and Moondancer, who were marveling at some of the patterns etched into the walls. Princess Celestia was either a very intricate designer, or she had simply gotten bored over the years. Simple Pleasure, still a little breathless, tried to organize an activity with the main body of fillies.

Trixie stopped them from heading over to join the group. “I’ve been wondering something about the Bank. There’s a room still unaccounted for.”

“The central room?” Twilight said. “You’re right, I couldn’t tell if it was supposed to be on the Sun side or the Moon side.”

“If it represents the Earth, then it’s probably not on either side,” Twinkleshine reasoned.

“Or it’s on both,” said Moondancer, looking through her book again.

Minuette and Lemon Hearts overheard them talking and came over. “Did you want to find the Earth room?” Minuette asked in a low voice.

Trixie raised an eyebrow at them. “Notice the slope of the floor?”

Twilight had, actually. It all sloped toward the same point, a small but perceptible valley.

“I bet directly under there is where the Numeraire is,” Trixie said.

“Which confirms the worst case scenario,” Twilight said. “If you have to go through the Gold Room to get to the Earth Room where the Numeraire is, then Princess Celestia really hasn’t checked on it in a thousand years.”

“You still have the key, right?”

“Yeah.” She had taken the Gold Key back from the guard, and though some fillies had asked to hold it, Twilight only let them reluctantly, and quickly swiped it back.

They moved in a huddle to the valley of the Gold Room. Though it was actually slight and nearly imperceptible, Twilight felt that the slope was deep and obvious, and she kept glancing over her shoulder to check that Simple Pleasure wasn’t about to pounce on them.

“Now what?” Lemon Hearts whispered.

Twilight bent low, inspecting the golden floor for anything resembling a keyhole, but aside from the slope, the floor was perfectly uniform.

“Try finding the Numeraire,” suggested Moondancer. “Everything in the Bank knows where it is by the way they move around it.”

Twilight pressed the Gold Key to sloped part of the floor. A force like magnetism tugged the end of the key toward the deepest point, and the key sank in. Twilight turned it.

Click.

A familiar golden flash of light lit the room as the door underneath them began to slide open. Twilight quickly retrieved the key as they all stepped back. She bumped into something.

“Well done!” said Princess Celestia behind her, beaming.

Twilight was too stunned by the sudden appearance of her princess to answer. Then the door fully opened, and a horrible suction yanked her into the dark tunnel. She saw Trixie, Twinkleshine and the others falling after her. A golden glow wrapped around them, and Twilight felt herself slow momentarily, but then she was torn free of the magical grasp and plummeted into the darkness below.

There was darkness, and weight. Twilight couldn’t move.

---

Simple Pleasure ran to the closed door. “Don’t worry!” she shouted at the floor. “Princess Celestia is going to rescue you! Stay put!”

“Don’t bother,” said Princess Celestia. Her expression was grim. “Nothing, not even my magic, can pass in or out of that door.”

Princess Celestia was summoning books from somewhere in her library and had five of them open at once, pages turning at different speeds as her eyes flicked over them.

“Can’t you go after them?”

“It takes both of us, or our agreement,” Princess Celestia said distractedly. “That was a precaution we chose.”

“Then send me!” Simple Pleasure was almost frantic.

“They have the key, and no.”

“Girls!” Simple Pleasure shouted at the closed door, even though she had been told it was useless. “You have to open the door from the inside! Use the key!”

“They can’t make the climb. There’s a magical draft that would stop even the most fearless weather Pegasus from flying up there. That was also a precaution.” Princess Celestia discarded two books. Three more floated up in front of her eyes.

“Why did you send them there?” Simple Pleasure demanded, whirling around.

Princess Celestia’s eyes closed for a fraction of an instant, as if in pain. “I underestimated how much One the Numeraire weighs. It tore them out of my grip.”

Simple Pleasure stood in front of Princess Celestia and glared at her, though she barely came up to the princess’s chest. “Get them out! Please!”

“I am trying,” said Princess Celestia mildly. “You’re blocking my view of several books.”

Simple Pleasure stepped aside, but was undaunted. “Are they in danger?” The princess’s horn was starting to glow intensely.

Princess Celestia frowned. “That...depends on where they choose to go.”

“Go?”

“Into the Silver Room, of course.”

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