Once upon a time there were two sisters. The elder, her hair the color of rainbow, which wasn’t then all that it became later, raised the money supply every day. The younger, her coat as dark as the space between stars, lowered it at night. Between them they maintained the balance between money and the economy of goods and services, the nominal and the real. For five hundred years the equilibrium stood with only one interruption.

After that incident, the two Alicorns took the title of Princess. Princess Celestia the elder, beloved by ponies everywhere, contented herself to watch Equestria’s economy develop. Princess Luna, however, was not happy.

When Princess Celestia raised the money supply, goods and services sold more easily. Income went up, and the ponies were slow to realize that each bit bought less than before. When Princess Luna lowered the money supply, goods sat on the shelves unsold. Ponies had fewer bits. That their bits now bought more did not impress them.

Whispers spread across the land. Ponies loved the beautiful, warm Princess Celestia. The dark, reticent Princess Luna they viewed with suspicion. Why did she need to lower the money supply? It hurt ponies.

Alicorns have good ears and long memories. Princess Luna wanted the same love that fell upon her older sister. Jealousy consumed her. Though her older sister tried to assuage her doubts, the seeds of discord took root in Princess Luna’s heart. The sisters commiserated less, fought more. Maintaining the equilibrium became a chore.

One night, Princess Luna made a mistake. The money supply dropped too much. Princess Celestia quickly restored the balance, but the recession rocked Equestria. Ponies marched on Canterlot that day.

Incensed at the ingratitude and ignorance of the ponies, Princess Luna discarded her crown. She turned her magic on the crowd, and her sister was forced to act.

The battle was terrible and brief. The earth does not easily bear Alicorn magic, nor can the economy stand against the Bank’s might unleashed. And in the end, it was the Bank that decided it. As their battle had initiated with Princess Celestia in control of the money supply, so it ended. Victorious, Princess Celestia banished her sister to the moon for a thousand years.

Some might say she overreacted. Spike did once, and Twilight Sparkle gave him the silent treatment for a week.

No pony from that time is alive today except for two, and only one was ever in a position to talk about it. This is the story she tells her students.

For the first time, the other Alicorn will get her chance to speak.

The six ponies walked past the gatehouse and into the spacious throne room of the great library of the castle of the Knights of Economics. Faded graphs, charts and equations were spread along the stone walls, though the room was curiously devoid of books. Crumbled stone and a thick layer of dust told them the space had long been abandoned. In the center of the room rested five crystals, each a different color. Behind the crystals was a throne, and on the throne sat Nightmare Moon.

She watched Twilight with evident interest. “Little economist, you have found your way to me.” Her voice was the smoke from a forest fire.

“As you can see, the Elements of Equilibrium are here.” She gestured at the five crystals. “But what you give up to acquire them may cost more than you realize.”

Twilight’s throat was dry. Her heart hammered in her chest. Her ribs throbbed as if in warning.

In front of her was the Alicorn who had unseated Princess Celestia, who had cast all of Equestria in shadow. Behind her were the five bravest, smartest and kindest ponies she ever knew, and in every direction she could feel the rapidly shrinking economy, the intricate web of production and exchange that Nightmare Moon was suffocating to death for her own twisted revenge.

Twilight was not afraid. Before her was the problem, behind her was the solution. All her training, all her knowledge and power finally had an opponent worthy of it.

For the first time, Twilight truly felt like the econopony she was. Naturally, she did what any econopony would first do.

“How many bits to stop?”

Nightmare Moon looked up. “What?”

“How many bits to free Princess Celestia, leave the Equestrian economy alone, and return to Charles his children?”

Nightmare Moon’s laughter echoed through the chamber. “Of course! An economist to the end. I’m afraid my price is too high for you.”

“Name it.”

“All the bits in the world. Which will soon be zero, by the way.”

“I’m willing to consider non-monetary compensation.”

“Such as?”

“Me,” Twilight said.

“Don’t make me laugh. What’s an economist worth when there is no economy?”

“As long as there are ponies in want,” Twilight said, “there will be an economy. Even you cannot stop that.”

“Watch me.”

“I don’t intend to. Girls!”

The best ponies Twilight knew stood beside her.

Applejack swiped her hoof on the floor. “Sweet Apple Acres has been going for centuries. Ain’t no pony changing that.”

Pinkie Pie bared her teeth. “I won’t rest until there’s a Sugarcube Corner on every street corner in Equestria. Anypony who gets in my way is going down.”

Rarity tossed her hair. “I couldn’t have said it any better. Besides, Princess Celestia is much more fabulous than this Alicorn.”

Rainbow Dash couldn’t keep her wings still as she hovered above them. “As long as I’m rich, no pony is taking my money away.”

“You need to go down,” Fluttershy said simply.

Nightmare Moon did not smile. “Who are these? Your friends?”

“They helped me get through the forest, yes,” Twilight said.

“How you must trust them.”

Twilight didn’t answer, unsure of what Nightmare Moon meant.

The Alicorn’s eyes gleamed with the absorbed light of a black hole.

“My sister taught you economics. Did she teach you wisdom?” Nightmare Moon cackled, a laugh of bubbling green nastiness and imminent pain.

A dark streak leaped with a crack from Nightmare Moon’s horn. Twilight watched helplessly as it swallowed up her five companions, encasing them in a shadowy prison. They beat on the walls with their hoofs, their mouths opening and closing, but they were inaudible to Twilight’s ears.

Twilight held up a hoof reassuringly, trying to calm the ponies down.

“A Slutsky matrix,” she said to Nightmare Moon. “Only semi-definite.”

“Old-fashioned, I know,” Nightmare Moon said. Now her voice was thick with exaggerated weariness. “I was away for a while. Can you blame me?”

“What do you want?”

“I remember how my sister and how she treated her students. The constant battery of tests. I would like a turn playing the teacher.”

Twilight’s eyes widened. “You cheater! We already passed your five tests in the forest!”

Nightmare Moon chuckled throatily. “Such traps as the forest set you are hardly my concern. But you passed no test. You allowed your friends to brave the dangers and sacrifice for your sake.”

Twilight didn’t deny it.“That’s the division of labor.”

“So convenient for those who do half the work and reap all the reward.”

“Start the test.”

“Of course.”

Darkness flashed from Nightmare Moon’s horn. Twilight flinched away, but Nightmare Moon screamed.

“DON’T LOOK BACK!”

The roar made Charles’s own sound like Fluttershy at her most timid. The very castle quaked from the force of Nightmare Moon’s voice. Twilight’s vision blurred, and it wasn’t until she tried to push herself up twice and failed that she realized she had fallen.

“You are forbidden to look at your friends or communicate with them in any way without my permission,” Nightmare Moon said. “If you disobey, you forfeit the test.”

Twilight shook her head, trying to clear away the residual ring in her ears. Her rib stabbed at her like a knife in her side.

“What happens if I lose?”

Nightmare Moon’s mouth stretched, became a twisted smile. “Guess.”

Twilight managed to get to her hoofs. “What do I have to do?”

Nightmare Moon’s horn flared again. Twilight’s treehouse that Princess Celestia had given her; the rolling green-and-red hills of Sweet Apple Acres; the Sugarcube Corner, a glass cube full of cake and ambition; Rarity’s white-and purple boutique that looked like it smelled like conditioner; the squat, busy stock exchange; and Fluttershy’s animal sanctuary appeared as floating images overhead.

“Are any of these places precious to you?” Nightmare Moon leaned on her other side, restless and watching. “They are precious to your friends.”

“What do you want?”

“Playmates, maybe, somepony who understands economics. Give up this pretense of challenging an Alicorn and return to Ponyville. You can do more to help Equestria alive and with some semblance of freedom than you can a vaporized pile of ashes.” Her eyes were amused, taunting. “Pray I should be so merciful, girl. Now what is your answer?”

“Huh?”

“Your freedom. You want it, girl, and you want to fight me. It comes at a cost.” Her dark horn burst again, sounding like a foghorn, and the images changed. Fire swept over Sweet Apple Acres. The glass walls of Sugarcube Corner cracked and crumbled. The Boutique blackened and turned a nasty shade of green in parts, decaying and dilapidated. Steel bars rose around the animal sanctuary, pressing inward until it was nothing more than a cage. The stock exchange was still there.

“What do you say, proud little Unicorn? Is it a deal worth taking?”

Twilight knew the trap, she also knew the truth. “Ye….”

Nightmare Moon smiled, the edges of her mouth sharp enough to cut.

Twilight thought she understood the setup. The ponies had been decent to her, but it was hardly a choice. Nothing mattered more than stopping Nightmare Moon, and to do that she needed the Elements. That meant giving the right answer and passing the test. Even if it meant some of the other ponies suffered, it was better than the entire economy being destroyed. Then everypony would suffer. So Twilight would have to take this offer, and in doing so, make everything that happened in the forest utterly meaningless. It reset everything, made the five ponies Nightmare Moon hadn’t accounted for a non-element. Clever.

Yet obvious. A thousand years trapped off-planet had damaged Nightmare Moon’s sense of subtlety.

It was an easy choice. So why when she had opened her mouth to speak had an image of Pinkie Pie’s bright, encouraging face in the maze of thorns appear? Why had she remembered the inner glow of Rarity’s assurances, how much a little sincerity had meant? The relief she felt like a starving pony tasting food for the first time in weeks when Rainbow Dash appeared out of the sky to rescue her from the sea serpent, the anguished helplessness and admiration as she watched Applejack fearlessly play the Cerberus’s game and accept the consequences to help her friends, Fluttershy’s painful courage in the face of a sea serpent whose need wasn’t enough, why did it assault her all at once?

Twilight opened her mouth again to announce her decision to betray the other ponies and found that she couldn’t.

No. I’m being stupid. They can’t even help anymore. Only I know economics, only I can pass the tests. I’ve never relied on other ponies, and I’ve certainly never sacrificed the greater good, even their own good, to save them.

But they helped you.

Princess Celestia’s voice. Twilight heard it whenever she argued with herself, whenever part of herself had realized something and was trying to teach the rest of her brain.

They faced what you couldn’t. How far through the forest could you have gotten by yourself?

I could have teleported past the Cerberus, blasted through the maze, fought the parasprites somehow—if Applejack hadn’t kicked me—

Unlikely—too many trials to overcome. Since when have you been in the habit of pretending that the strength of other ponies is your own?

Here is the truth. These good, brave ponies saved you. They risked, sacrificed, bore pain, fear and sorrow so that you could reach this place. They chose to cooperate with you, and you cannot betray that, not if you ever want anypony to cooperate with anypony ever again.

There won’t be any more cooperation if I don’t defeat Nightmare Moon!

It is amazing how often ponies find that they have no choice but to sacrifice others for the greater good when doing so is convenient to their own ends. Nothing is ever so certain. Stop, think…is there another way?

Twilight caught her breath. She hadn’t realized her own agitation. Calm, slow, she told herself. Nightmare Moon apparently intended to set her free if she chose to accept the deal, confident that none of them could do anything to stop her.

Was that true?

One the one hoof there was Nightmare Moon, the Alicorn sister as powerful as Princess Celestia, with absolute control over the Bank and powerful ancient magic that could snuff out half a dozen ponies in an instant. On the other hoof there was an econopony and five rather silly, chaotic ponies from a backwater town where the roads were made out of dirt, and they thought books were something you kept in the bathroom in lieu of toilet paper. The same five ponies, Twilight realized, who had fought their way through the Everfree Forest, something that hadn’t been done since the Alicorns and the days of the Knights of Economics.

Five ponies. Five elements. As Pinkie Pie would put it, duh.

Somehow Twilight had always imagined herself wielding the Elements of Equilibrium. But it was they who had passed the tests, not she. It was they who were worthy. And now it was time for her to face the danger so they could pass through.

Nightmare Moon did not understand the forces she had brought upon herself. Locked alone in the moon for a thousand years, she had forgotten about the power of cooperation.

It sounded good. Twilight didn’t know how they would fight Nightmare Moon. But she had to try.

“No,” she said. “I refuse.”

For the first time, Nightmare Moon looked genuinely pleased. “Good! You’re so loyal. You will have to be to earn these Elements.”

Twilight struggled to offer a reaction; she already knew they weren’t meant for her.

Nightmare Moon continued. “But your little helpers are not. TURN AROUND!”

Twilight was spun around so fast she didn’t know if it was magic or fear. She stared with numb dread at her friends through the murky black wall of the Slutsky matrix. Six images like what Nightmare Moon had showed her hovered above her friends.

“They don’t know you can see them,” Nightmare Moon said, voice thick with amusement. “Any predictions, little student of mine?”

Twilight watched five hoofs belonging to five different ponies reach up and touch the treehouse, which trembled and fragmented, books spilling out and decaying into dust. She had expected it, but it still hurt to see.

Twilight stiffened. She heard Nightmare Moon leave the throne and walk up behind her. No heat came from her body. Instead she felt coldness, coldness like sheer emptiness.

Her breath on the back of her neck was like ice cubes. Twilight shivered.

“Maybe they wanted something else from you,” Nightmare Moon said. “Somepony who read less, was more agreeable.”

Twilight shuddered; she couldn’t help it. “Shh, shh,” Nightmare Moon said, drawing her in with a leg as cold as frost and crackled like electricity when it touched her coat. “Now I’ll do away with this matrix. You know what happens next, don’t you?”

“Y-You told them that they have to do it now,” Twilight chattered. Her jaw felt stuck; it was hard to speak. “I’ll have to fight them when they come out.”

“Ready, faithful student of mine? Is your horn sharp?”

She doesn’t know. She thinks it’s me. It’s not me.

“I won’t fight them,” Twilight said.

“Yes!” Nightmare Moon chuckled, high and pleased. “Yes!”

The sound of Nightmare Moon’s laughter struck fear into Twilight’s heart. She realized she didn’t understand what Nightmare Moon wanted. She realized she was fighting a being as older as she was more powerful than her. There was no battle of cunning she could win here.

Twilight saw the edges of the dark glow of Nightmare Moon’s horn. The matrix burst apart in purple tatters.

All five ponies rushed out toward them with murder in their eyes. “Stop!” Twilight cried. She had seen their intent to attack Nightmare Moon. But that wouldn’t do, she needed them all safe and alive.

The Alicorn was back on her throne, though the chill in Twilight’s body remained. She looked curious and eager, like a scientist about to check the lab results, or like a cat waiting to see where the mouse will run next.

“Let me at her!” Rainbow Dash said. “She’s not cooping me up again!” Applejack was standing on her , though, and Twilight guessed that Rainbow Dash might not be trying too hard to escape and find herself facing off with an Alicorn.

Twilight looked at the banished princess on the long-abandoned throne, mind racing. She had been wrong again about Nightmare Moon’s plan. What was…

…above the throne and black wings and sharp horn, six images floated in the air, a treehouse whole and unblemished, and five dreams discarded, evidence of an act more evil than any she had seen nightmare moon commit.

Applejack, Pinkie Pie, Rarity, Rainbow Dash, and Fluttershy looked.

“What’s that?” Pinkie Pie said.

“You did it too,” Twilight whispered. She wished Applejack would kick her in the ribs again instead of look at her like that. “I saw, in the matrix—”

“She asked us to pick which part of Ponyville we wanted to save,” Rarity said. “I suppose it was the same for you? We had to choose the Golden Oak Tree, of course, since you live there and have to stop Nightmare Moon. Besides, it’s older than Ponyville! Aha, by the way, the Alicorn in question is right there, do we have a plan? I think I’m learning that I tend to talk when I’m nervous—mmph!” Applejack had put a hoof in her mouth, which Rarity accepted after a moment’s surprise. Rainbow Dash took the opportunity to jerk herself free, but didn’t fly forward.

Nightmare Moon watched Twilight with anticipation that burned like an iron brand. “You see, little heroines, I asked my student to choose which parts of Ponyville would be destroyed during my rule. In the end she chose to save what was hers and leave to ruin your own capital. This is the gratitude she has for all you did to carry her through the forest.”

“She did a bit of carrying herself,” Applejack said sardonically.

“It was the same choice,” Twilight trembled. “Just backwards.”

“It’s not the same choice at all!” Pinkie Pie said. “She let us push a friend up. Ooh, she’s evil!”

It took Twilight a moment to understand; it also took her a moment to realize that Pinkie Pie was addressing her rather than Nightmare Moon.

She had no idea what Nightmare Moon was trying to do. She suddenly realized she didn’t care.

Twilight smiled at the five ponies she trusted more than anypony in the world. “One more trial, girls. Thanks for sticking with me so far.”

Shock and confusion flashed across the tall Alicorn’s face, quickly replaced by disappointment and boredom flashed across the tall Alicorn’s face. “Foolish,” she spat. “Get out of my castle. I have a world to destroy.”

“Give me my money back!” Rainbow Dash said.

“Leave,” Nightmare Moon said.

“Not until you return Charles’s children,” Fluttershy said.

Nightmare Moon looked at her.

Twilight quickly took a few loud steps forward. “I’m not finished with you, Nightmare Moon.”

“The tests are through,” Nightmare Moon said. She sounded severely unhappy, even confused, like a child whose birthday had been canceled because the paperwork hadn’t been filed properly. “You failed. Take your friends and find a hole in Equestria where you can hide for a thousand years. I will see no more of you, Twilight Sparkle.”

“We’re free, so we’re freely choosing to stay right here. A little bit of cheating is allowed.”

CRACK.

The ponies flinched. Nightmare Moon withdrew her hoof from the hole in the stone floor.

“That was not magic, little ponies.”

Nightmare Moon set the five crystals by the throne and turned away. “I have things to do, an economy to destroy, a sister to…hm, is there a word for the act of totally eradicating every component of somepony’s utility function? No matter. Leave.”

Only one chance. Failure meant death. Failure was probable.

Twilight spoke.

“Still overshadowed by your older sister, Nightmare Moon?”

Twilight would never forget the face she saw then. For a moment Nightmare Moon’s eyes were darker than the void, her cheeks sharper than dragon teeth. If looks could kill….

…It was, thought a rebellious part of Twilight that she hadn’t known existed, exactly the sort of look a pony might develop if she had spent a thousand years in isolation in the moon.

“What did you say?” Nightmare Moon’s voice was low, even soft, like a panther allowing its padded feet to fall with just enough sound for the baby bunny rabbit playing in the meadow to notice at the edge of its hearing, because it wants the bunny to run.

Only a baby bunny had a better chance of kicking a panther to death than she did of fighting Nightmare Moon.

“It’s been a thousand years to us, but I suppose to you things haven’t changed.” Twilight didn’t feel like smiling, but she did. No, she smirked. She smirked like Trixie, like she knew exactly where Nightmare Moon’s weaknesses were and nothing could stop her from going after them in front of everypony. “It’s still all about Princess Celestia to you.”

The dark Alicorn narrowed her eyes. “I defeated Celestia. She is gone.”

“Not from your head.” Twilight giggled, high-pitched and knowing. “You have no real goals of your own. The best you can do is the opposite of what Princess Celestia wanted. After you destroy everything, you’ll realize that even now you were just obsessed with your sister.”

Was it Twilight’s imagination, or were the shadows from the walls growing, reaching toward Nightmare Moon. And was Nightmare Moon herself getting bigger, or was that just a trick of the dimming light?

“Twilight,” Applejack gulped, “maybe you shouldn’t talk that way to the Princess.”

Shut up, Applejack. I need to keep all her attention on me for this gamble to pay off. If she thinks about even one of you….

“She’s not a Princess,” Twilight said. “She abandoned her crown when she turned on the people of Equestria. If Princess Celestia hadn’t—”

“LIAR!”

The noise went off like an explosion inside her skull. Twilight didn’t know how long it took before she managed to reorient herself. Something wet dripped from her ears. For a panicked moment she flailed her legs in midair before realizing that a dark glow had surrounded her.

She looked up into the terrible face of Nightmare Moon.

“I would rend you, crush you, break you in every way for that insult and never stop.” Nightmare Moon seethed with a fury magnitudes beyond any emotion Twilight had ever felt before, the difference between a millennia of pain and the short life of a young Unicorn. It set her hair on end, piled goosebumps on top of her skin, and even still her whole body buzzed with the sheer raw hurt of it all. “But I know it was my sister who told you that lie, and it is she who will bear my wrath.”

Twilight struggled against Nightmare Moon’s magical grip. She couldn’t see or hear any of the other ponies. The realization hit her worse than a kick to the stomach. If even one of them was hurt….

“It’s not a lie,” Twilight said. “Princess Celestia told me how she was loved and you weren’t, the jealousy that grew inside you, how you turned on the ponies—”

Twilight cut off, mainly because she couldn’t breathe. An invisible, sourceless pressure weighed down on her with a uniformity and evenness over her entire body that would have been fascinating if it hadn’t been crushing her. Something in her fractured ribs gave. Twilight was almost glad she couldn’t make a sound.

“My sister lied. I will show you the truth.”

“Once upon a time,” Nightmare Moon sneered, “there were two sisters, the elder who raised the money supply and the younger who lowered it. They defeated the snow and the forest and the draconequus, and a dozen other enemies in their time, but the short-lived ponies with even shorter memories were not grateful.”

The psychic grip she had on Twilight lessened. Twilight sucked in air through brief, pained gasps even as her eyes widened at the sight Nightmare Moon showed her. She saw them as clear as a dream, the two Alicorns who founded Equestria, the two sisters as different as day and night.

“My older sister was beautiful, kind and warm,” Nightmare Moon continued. “All the ponies loved her. During the day she visited them, spoke to them, and when they begged for her magic to solve their pathetic problems, she obliged. I, however, never much cared for the company of ponies, always preferring instead a book and a quiet place to read.”

Twilight flinched. It was only superficial, it didn’t mean anything, but the very idea of having something so personal in common with Nightmare Moon shook her.

“I was a fool,” Nightmare Moon said bitterly. “I was powerful, but they did not know me as one of their own. I helped them, but they were not forced to see this, and so they chose not to. My role in keeping the equilibrium was vital, but there were those who said otherwise, and when they had repeated their lies and fallacies enough, it was a controversy, not a slander. They wanted Celestia to have my power, to have total control over the Bank.”

Twilight saw.

Celestia strode into the private study of the five hundred year-old castle, her crown dangling from her horn. “Sister!”

Luna, smaller, brighter, happier, looked up from her book. “Ah, Celly! Have you ever wondered why better goods are sold over longer distances? Canterlot makes the best fabrics, but have you noticed you have to go out of the city to actually buy them?”

Celestia frowned. “Can’t say I have.” She didn’t sit by Luna but instead flopped in a chair a table away, a troubled expression on her face.

Luna carefully set a thread to mark her page and set the book next to her crown on the table. “What’s eating you? Not more parasprites, I hope.”

“No. Almost. Just…ponies. Foolish ponies with foolish ideas.”

Luna smiled. “You’ll find no rest here. Even in this library there are too many foolish ponies with foolish ideas. Seriously, can I help?”

“No,” Celestia said. “I will deal with them.”

But Celestia’s mood only worsened over the months and years. Every day as the sun came down and she returned from her visits with the ponies, Celestia was moody, angry, and short-tempered.

“I am worried about you, sister,” Luna said one evening. “If the ponies distress you so, why do you speak with them?”

“One of us has to maintain confidence in the Bank,” Celestia said. “Worry about yourself.”

“You are who I care most about in this world,” Luna said. “Worrying about you is worrying about myself.”

Now they were on the edge of the Everfree Forest, wilder then and layered like mountains. Princess Celestia’s golden magic glowed over the three bite marks on Luna’s flank and legs.

“I was inattentive,” Luna said. "Caught unawares."

“Yes,” Celestia mumbled.

Luna glanced at her and said nothing.

In the gold and silver chamber of the Bank, Celestia slammed her hoof against the wall. Any other wall would have shattered from the force of the blow.

“Sister, I do not know why you are so angry,” Luna said. Seeing Celestia like this scared her. “It is only the talk of ponies. They die fast and do little with their lives. Nothing will disturb the equilibrium.”

“It is not the power of the ponies that concerns me,” Celestia snapped, “but the meaning of it. We are their saviors, guardians and protectors from threats from without and within. When they dare belittle you—”

“It matters not,” Luna said. “Peace, sister, I need no friends as long as I have you and my books.”

“Your gratitude overflows. I am drowning in it.”

Luna shrank back. “I am speaking out of concern as your sister, nothing more.”

Outside the castle in the center of Canterlot. Celestia faced the crowd of angry ponies at the dark midday.

“Only one mistake in half a millennium is proof of the quality and value of my sister’s wholly voluntary service to Equestria,” Celestia’s magically enhanced voice boomed. “This behavior does not become you, ponies of Equestria.”

But when Luna stepped out, the crowd’s noise multiplied with curses, jeers and insults. Luna wavered, suddenly longing for the dusty solitude of the library, but Celestia was incensed.

She rose. The sky warped and distorted as if a giant magnifying glass had been placed there, and it angled on the ponies who swarmed below like so many ants….

“My dear, sweet sister loathed the way they spoke about me,” Nightmare Moon drawled. “She pointed out that we did the same work, that we were two parts of a whole, that I deserved as much adoration as Celestia. The crowd didn’t seem impressed by the facts. Crowds generally aren’t.

“They went back and forth for a while, my sister and my accusers. Eventually lovely Celestia lost her temper. She let the crown fall from her horn.”

“No,” Twilight said.

“Yes. My lovely sister and your Princess turned the sun’s blaze upon the crowd. I stopped it with my own body. It seems the only thing that angered my sister more than attacks upon my reputation was my own lack of gratitude for her ‘help.’

“We fought. I lost. What you know of what happened after may also be lies. I do not know because I was getting acquainted with my prison in the moon at the time.”

“Not true,” Twilight managed. “None of it.”

“Oh, you think she banished me for a thousand years because that was the REASONED RESPONSE?”

The dark glow surrounding Twilight vanished. She managed to land on her soft rump, but there’s not much that can make an impact feel less painful with a shattered ribcage. At least her bones were vocal in their appreciation of her futile attempts to hold her body still.

Nightmare Moon was changing. The blackness-beyond-blackness that was her coat faded into her skin, or maybe a dark purple unsettlingly close to Twilight’s own lavender shade grew over the black. She didn’t hold herself as tall. The pony who had been Princess Luna raised her head.

But it was still Nightmare Moon. Her narrowed, hateful eyes made that abundantly clear.

Dark interlocking circles marred the right side of her body. They looked like—

“Scorch marks,” Nightmare Moon said. “Too much sun is terrible for your skin.”

The purple sank beneath the black, or maybe the void grew over her again. She turned to the window and looked out. “Ironic, isn’t it? My sister only wanted to protect me. And here I am, trying to protect the economy from inflation. A…cycle of sorts, wouldn’t you say?”

Twilight’s mind pushed her eyes away from the distant Alicorn and toward the five crystals resting by the throne.

“Twilight!” a voice whispered. “Are you—”

Twilight’s magic held Rainbow Dash’s lips together. They were okay. Her friends were okay.

She released Rainbow Dash and called the Elements to herself. Each had its own shape. One looked almost like two hoofs meeting. A second was more like a maze, though Twilight couldn’t make out any path through it, and a third looked like a cloud, or maybe a marshmallow. Another had the shape of a jagged line, almost like a lightning bolt, or a graph of price movements. Finally there was something abstract that reminded Twilight of the pony brain.

Twilight gazed at the five frightened ponies behind her who somehow believed that she could defeat Nightmare Moon.

They had all made the same mistake. Twilight was an economist. It wasn’t her job to restore the Equilibrium but to name and know its parts.

She pinned a crystal to the chest of each pony.

“Now, girls!” she cried. “Do it!”

But what she wanted them to do she never got to say, because the air shot out of her lungs and her vision went black.

Twilight awoke to pain and the weight of an Alicorn kneeling on her.

“Tell your friends to drop those crystals,” Nightmare Moon said, “or I’ll start hurting them. The white Unicorn gored, perhaps.”

Offering me a concrete visualization, thought the automatic, ever-vigilant analytical machine that was her brain, while the rest of her panicked. Specifics, a single image to get through my defenses.

Nightmare Moon was talking.

“Strangely, when I threatened to hurt you more if they didn’t drop the crystals, they seemed unmoved. The margins of friendship end where the costs begin, I see.”

It did hurt, it did almost move her. Is this symmetry, defecting because they defected, or is it conformity, doing whatever the other ponies are doing?

Nightmare Moon pressed on her.

One signal in Twilight’s brain sent her writhing for air and another responded sharply with pain.

Nightmare Moon allowed more of her weight to sink onto her. “They can’t hear you. Speak up.”

“Not a cycle,” Twilight gasped.

Nightmare Moon looked down sharply. “What?”

“You said…something about a cycle before. It’s not a cycle.” Twilight breathed. Breathing hurt. She did it anyway. “There is no business cycle, just bad monetary policy.”

“Pain is usually a better motivator than this,” Nightmare Moon sighed. “My sister brainwashed the most foolishly devoted pony I’ve seen in a thousand years.”

“You know…I’m right,” Twilight said. “That’s why…you haven’t attacked. They’re the Elements…of Equilibrium!”

Twilight’s vision went so black it turned red. She couldn’t even properly describe what she felt as pain. The instant it ended the gulf between the memory and the actual feeling was so large she wasn’t entirely sure if it had even happened.

“I will keep doing this,” Nightmare Moon snarled. “Now tell your little friends to drop the crystals.”

“Twilight?” Pinkie Pie’s voice. “What should we do?”

Twilight chuckled, and immediately regretted it. “You made two mistakes, Nightmare Moon. The first was uniting the Elements with their Bearers.”

“These little ponies couldn’t bear so much as a strenuous hike.”

“No. Applejack, who gave her hat to promise the Cerberus that she would fulfill the terms of the agreement demanding her very life, represents the spirit of…contract!

“Pinkie Pie, who guided us through risk, uncertainty, and a terrible maze of thorns, represents the spirit of…entrepreneurship!

“Rarity, who out-gossiped the parasprites and drove them away with sincerity represents the spirit of…information!

“Rainbow Dash, who took us all from the far side of the moat past the dragon to where we needed to be faster than anypony could have represents the spirit of…finance!

“And Fluttershy, who kept us from distraction and on the path of defeating you, represents the spirit of…rationality!

“Together they are the Elements of Equilibrium. Together they are your doom.”

Nightmare Moon watched them. “But they’re helpless as long as I have you.”

“She’s right,” Applejack said. “I feel something…strange coming from this crystal and it’s meeting something coming from me, but I can’t do nothing while she’s got you.”

“Doesn’t matter,” Twilight said. “Get her! I’m not important anymore.”

“We’re not abandoning you!” Rainbow Dash said.

Twilight managed to lift her head. “Fluttershy, tell them.”

“No,” Fluttershy said. “None of us would have even gone to the forest without you. Each of us did our parts as individuals, but you got us here as a group. You can’t just stand to the side and watch. You’re part of the equilibrium too.”

Twilight’s eyes widened in shock, and then in pain. Nightmare Moon laughed.

“You ponies are sickening! Just like my sister, you try to protect each other but end up destroying one another. Isn’t the irony delightful? I think I’ll make the white one gore you all one by one.”

Part of the equilibrium…?

“Your remember so much from so long ago,” Twilight gasped. “But there’s one other thing you forgot. I can teleport.”

“Wha—”

Twilight vanished in a lavender burst of magic and reappeared at the head of her five friends.

“Girls, fire!”

If you shoot a beam of white light through a prism, it separates into the seven colors of the rainbow.

If you shoot a beam of pure, undiluted friendship through an econopony…

…You get something similar.

The rainbow faded, as they do, but the promise lingered. As golden light blazed like the sun in the ancient castle, a smile spread over Twilight’s face.

"I’m part of the equilibrium too."

She collapsed into the hoofs of her friends. It was some time before she woke up.

Don’t worry. She was fine. This is a story about magical talking econoponies learning together about the science of friendship—er, economics. There will always be a happy ending.