After jumping out of bed at the noise, the ponies couldn't help but stare at the procession that was trotting down the street in the middle of the night. Sure, it was mostly because the leader of the convicts being held by the royal guards was Princess Luna, one of the rulers of Equestria. Not only were her forehooves chained together, there was an anti-magic ring clamped around the base of her horn, and her wings were tied to her body, leaving no doubt that Princess Luna was being faced with criminal charges. However, that fact wasn't the only thing that drew ponies' attention.
It was also the expression on the princess' face. She looked angrier than any of her subjects had ever seen her. Her eyes burned with a cold fury that any foal would be terrified to see. She didn't even spare the ponies on the street a half-second glance, but marched onward, staring straight forward. The other criminal ponies in the line all had varying expressions, some looking lost and sad, some turning to rage instead, but none came even close to equaling the depth of Luna's emotion.
Naturally, everypony wondered what one of their beloved princesses had done to warrant this treatment. Sure, Luna had been gone from the castle for the past couple of weeks, as Princess Celestia had told them, but the moon had still risen every night and lowered every morning. This had led ponies to believe their diarch was simply on vacation. Apparently, she'd been committing some horrible crime against Equestria.
But what?
Princess Celestia once again fought the urge to simply spread her wings and fly out of the courtroom, leaving her advisors to deal with the impending trial. But she knew she had to be here, in order to set an example for the rest of her little ponies, especially considering the identity of the accused. That didn't mean she had to like it, of course. In fact, she hated the idea of presiding over her own sister's trial. But if she didn't, ponies would accuse her of showing favoritism to Luna, or see it as a sign of weakness to be exploited. She had enough to deal with without fueling rebellious thoughts among the population.
Her heart ached as she recalled how her scouts had informed her of Luna's activities. Her sister had left the castle just a few weeks ago, claiming she needed a break from being a ruler. Celestia had let her go, seeing no reason to stop her. But as time went by, and Luna sent no letters, she became worried that something terrible had happened, and sent out the royal guard to investigate. Her relief upon learning her sister was just fine was quickly decimated by the knowledge of exactly what Luna had been up to, and the fact that she'd had to issue an order for Luna's arrest. The only mitigating fact was that Luna had surrendered without a fight, but that also puzzled Celestia. Why didn't she fight back if—
The princess' marinating in her own thoughts was interrupted by the doors to the courtroom slamming open. The guards trotted in, leading Luna and about a dozen other ponies inside. Luna wasted no time in making eye contact with her sister, sending an enraged glare her way. Celestia actually shivered at the sight. She and Luna had their disagreements, of course, but she'd never seen anything like the raw, unfiltered hatred in her sister's eyes. The worst part was the fact that she didn't understand where it was coming from. She'd done nothing to Luna, nothing that could've prompted her to despise Celestia so. Some of Luna's co-defendants also gave Celestia the evil eye, but she barely noticed.
"Everypony settle down," said Arcane Force, the most trusted unicorn minister in Equestria. "Court will now convene for the trial of Princess Luna and her associates. The charge is conspiracy against the nation of Equestria. Princess Celestia, may we begin?"
Celestia forced herself to behave like Arcane was. Hard, cold, and detached from the situation at hoof. "You may," she responded, keeping her voice as level as possible.
"Thank you, Your Majesty," said Arcane. He lit up his horn, levitating up a scroll to his face. "Princess Luna, you were discovered by our scouts to have assembled a group of ponies that were planning to annex off a section of Equestria to make into your own country. You were in the process of recruiting more ponies for this plan when you were arrested. Do you deny these actions?"
"No," was all Luna said. Her eyes hadn't left Celestia's the entire time.
Arcane didn't seem to notice her hostility, and kept reading. "Your actions were committed without the permission of the Equestria government, meaning they amount to treason. Do you contest this charge?"
"No," Luna said again. Her voice was so cold, Celestia shivered on her seat.
"Now we move to evidence," Arcane continued. "We have eyewitness statements from our scouts who copied down the words you spoke. In addition, three of your co-conspirators for the so-called Lunar Republic have confessed to everything you were planning and given the information to us. Based on this, your guilt is irrefutable. Do you have anything to say in your defense?"
"No." Celestia swallowed, wishing Luna would explain this. She would've taken anything other than the silence.
"This court finds you and your co-conspirators guilty on all charges. Princess Celestia will be the one to decide on your sentence. Princess, I yield the floor to you."
Celestia uttered a furious curse in her thoughts. This was the part she'd dreaded. She'd hoped Luna would contest the charges so she could drag the trial out for as long as possible, and Celestia would be able to wait it out. But that dream had been dashed. All she could do now was punish her own sister.
"Princess Luna," she declared, "you have betrayed your oath to Equestria, going behind all of our backs to try and gain power for yourself. For this crime, you are hereby stripped of your titles, and will be imprisoned, until such a time we deem you worthy to be released back into society. Do you have anything to say in your defense?" This was the one time she prayed Luna would say no.
Those hopes quickly died as Luna sat up, stared deeply into Celestia's eyes, and began to speak. "Yes, sister. I do.
"Once, we were truly equals in Equestria. Everypony looked up to both of us. I truly felt like I belonged in this land, and I was happy to rule alongside you. But as time went on, our little ponies began to play more and more in the light of your sunny days, and ignored my beautiful nights and all the work I put into them. Ponies began to act like I didn't exist at all, even as I patrolled their dreams to help them with the worst of their nightmares.
"I went to you so many times, asking you to do something, make a speech, anything to help me, remind ponies that I matter as well. What did you do? Nothing. You dismissed my concerns, told me that 'ponies love me just as much as you' despite evidence to the contrary.
"You want to know why I was going to break off from Equestria? Because of you. Because you took all the attention of our little ponies for yourself, and I just wanted a piece of the pie. I was just going to take the hooful of ponies who actually appreciated my night and live in peace away from you, but of course, you won't allow that. So this is all on your head Celestia."
Celestia actually flinched like she'd been stabbed in the chest. She should've known that was the reason. It was true, after all. Luna had come to talk to her quite frequently to talk about how ponies were ignoring all the work she put into the night sky. Celestia had tried to comfort her sister, saying that there were ponies who loved the night, and many ponies appreciated Luna's dream work. However, she hadn't done anything herself to help Luna get more appreciation. Luna was right, this was her fault.
However, at the moment, it didn't matter. Or rather, it couldn't matter. Celestia had made her bed, and now she had to lay in it. Luna couldn't be allowed to walk free after trying to break off part of Equestria for herself, or it would set a dangerous precedent.
"It doesn't matter," she said, forcing herself to stay calm. "You will serve your sentence. Guards, please remove the defendants from the court."
The guards moved to obey, but Luna wasn't finished.
"What happens next is on your head as well, sister. All the ponies that will suffer and squirm will know you are to blame."
Luna's horn began glowing with its signature blue aura, though it was dulled thanks to the anti-magic ring. Celestia wasn't surprised she was able to summon a little bit of magic, considering how much more powerful magic alicorns had than unicorns. She started to worry when sparks began flying from Luna's horn, and the ring began to glow, as though heating up.
"Stop her!" she shouted, as she lit up her own horn, spread her wings, and dived off her seat. The royal guards charged towards Luna, but before anypony could reach her, Luna's horn released a blinding flash of light, and the anti-magic ring burst with a thunderous crack. With her powers free, Luna stomped her hoof, sending out a shockwave of pure energy that sent everypony within thirty feet of heart flying. Celestia barely managed to raise a golden shield to absorb the attack.
"How did you...?" she demanded, as her sheer shock prevented her from getting out the full question.
Luna laughed, and the sound was cold and cruel, so unlike her usual laugh. "When I learned you were coming for me," she responded, "I reached out, and made a deal with another party, when they offered me more power than you could ever hope to achieve."
Luna's horn flared to life once more, and another blinding flash eclipsed her from Celestia's view. When the alicorn's vision was restored, Luna had changed. Her normal dark blue coat had darkened, her eyes turned turquoise and narrowed to cat-like slits, her teeth had sharpened into fangs, and she was decked out in blue armor with moon insignias on it. Her wings were no longer tied up, and spread to their maximum width.
"Luna?" Celestia ventured, unable to keep the terror from creeping into her voice.
"Luna's not here anymore, sister," snarled the dark alicorn. "You may address me as Nightmare Moon." Her horn glowed and the glow of the moon coming in through the windows intensified. "Now, ponies will have to appreciate my night, because morning will never come!"
She cackled, before pointing her horn at Celestia. The solar alicorn didn't even have time to blink before a blast of black lightning lanced forward, blasting her in the chest and sending her into one of the stone walls. Nightmare Moon took off from the ground with a single flap of her wings.
"Farewell, Celestia. I think I'll begin my new reign by destroying everything you hold dear," she announced. Then she blasted a hole into the wall of the courthouse, and flew away, leaving Celestia alone with a room full of frightened ponies.
"Princess?" Arcane asked, walking over to her as she began to climb back to her hooves. "Are you alright?"
Celestia coughed, before shaking off the dust and rubble that had settled on her back. "I'm fine," she lied. "She only hit me once."
"Princess, what are we going to do?"asked Arcane. "How will you recapture the former Princess Lu—I mean, Nightmare Moon?"
Celestia looked to the sky, at Luna's beautiful silver moon hanging there. She did have the power to lower it, but she knew...Nightmare Moon would simply raise it again. She knew, after taking that attack, she didn't have the power to equal her counterpart.
But there was something that did.
"Arcane," Celestia began, "go to my vault. Retrieve the Elements of Harmony."
Her heart was in her throat as the minister ran off to fulfill her order. She hurried to calm everypony else in the room down, knowing that she was the cause of their misery. All because she'd had to enforce justice on her own sister.
Luna had surrendered because she'd wanted to do this. To hurt Celestia as much as possible by showing her how this disaster was all her fault. And now, Celestia would be forced to use the Elements of Harmony, the very weapons that had turned Discord to stone, on her sister, in the name of the law.
