Nightmare Moon sat on her throne in the dark, tapping a hoof as she thought. The sun had set already, and all around Equestria ponies were starting to dream. She could feel them as they crowded together into the back of her mind, calm and subdued but still an undeniable presence. Always there for her to reach out to should turmoil grow. She could only hope that this night would be a peaceful one.
She had ordered the guards to leave her. Applejack was sound asleep in Luna’s bed. Nightmare Moon was alone, and she intended for it to stay that way. She wanted nothing to interrupt what was to come.
All that remained was to decide how to do it, and she was having more difficulty with the decision than she had expected. Twilight was right when she suggested that bringing her back would be a strong first move. What guarantee did she have that Celestia would stay and listen, though? The guards would not stop her, and if Nightmare Moon herself moved to keep her in place it would only raise tensions more. The last thing she wanted was for this discussion to turn into a fight, because while she knew she would win, it was not a victory she sought.
The alternative was to meet in her dreams, but that option wasn’t ideal either. She would be sacrificing that powerful first move, and while keeping things how they stood lowered the risk of things turning ugly, it hardly made it impossible. Combined with the power she would have in her own dreams, and Nightmare Moon’s memories of her own dreams on the moon, it was difficult to commit to that course of action.
There was, also, a third option. She could go to the sun herself, and confront Celestia there. She had no idea what to expect there, though, and thinking back on how horrid the moon had been… No. She would never return to such a place again.
Somewhere in the castle, a clock rang out. Another hour gone. She needed to make a decision.
So, she cursed herself under her breath for deciding to do something so asinine, and then closed her eyes and reached out to the world of dreams.
The dreamscape welcomed her like an old friend. The vast, inky blackness, no floor or ceiling, no earth or sky. Just darkness in all directions, speckled with pinpricks of light left by dreams. Her own personal stars.
This wasn’t where she needed to be, though. No matter how far she looked, she would never find Celestia dreaming here. If she were that close, then Nightmare Moon would have been able to reach back into the world of dreams from the moon. No, dreaming in these places sent you somewhere else, someplace she rarely dared to tread.
She took a deep breath, then another. Even as Nightmare Moon, this trip was difficult for her. Eventually, when she felt ready, she slowly raised a hoof high into the air. Then she moved it forward, just a little, and felt it tug at the essence of reality itself. Finally, in one brisk movement, she sliced down through it to tear a deep gash into the world of dreams.
The tear was felt in every dream being dreamt, no matter how far. There was a sound unlike sound, as though the noise itself had been torn and distorted, and reality faltered. It was like a record skipping a beat that wasn’t there in the first place; wrong, altered, yet entirely the same. Completely unnoticeable, and at the same time digging into the deepest parts of who you are.
There was nothing to see where Luna had torn the world open. Really, she hadn’t torn open a place at all. It was more like she had put the idea of an opening into the world, and then made the idea true. It was always there, and no matter where she was, or how far she went, she could step through it at any time.
She didn’t have anywhere else to go, though. She just stepped through.
The gash mended itself behind her after she crossed, and just like that she was lost, stranded in a world that was not her own. Like hers, this dreamscape was an endless void, but it wasn’t the bottomless darkness she knew. It was something brighter, warmer, that she couldn’t quite grasp. It was as if all of it, the color, the shape, the idea, could find no hold in her mind, and she lost it as soon as she saw it.
That was everything.
There were no landmarks, no stars to light her way. This was not a place where dreams should exist, and so, for the most part, they did not. With her passage in gone, Nightmare Moon was stranded, lost to float aimlessly with no sense of where she was.
Except that wasn’t entirely true. She knew Celestia was here. With her consciousness shifted into this new place, her connection to the ponies of Equestria was gone, and so she could feel only one. A single dream, far away, that she knew to be her sister’s. All she had to do was find it.
It wasn’t easy. She truly had no frame of reference, no up or down or left or right. She knew she’d see Celestia’s dream somewhere, but she didn’t know where she had already looked. She could look too far up, only to have flipped around and started looking behind herself without realizing. Combined with the strain of meticulously scanning the distant something that made up this world, finding a single point of light was no easy feat.
She looked, and she looked. She looked for far longer than she had any way to keep track of, and then she looked some more. For all she knew, she could have been looking her entire life by the time she found Celestia, but eventually, she did find Celestia.
Once she found her, that was it. Her dream was unfathomably far away, yes, but distance meant little in this place. So far as she knew where it was, Luna could enter the dream in an instant.
She hesitated, though. This dreamscape was bad enough; the dreams were something altogether different. She had to work herself up to it, grit her teeth and brace herself, and then she jumped into the dream.
It hit her immediately. The rules were different here, existence shifted with the tides of the dream, and diving into it was an extreme shock to her system. The world around her was nothing but flickering reds and oranges, licks of flame that had no source and had no end, and they ran deep. The flames dug into space, they dug into time, they dug into being, and at the very core of herself Nightmare Moon could feel them burning away at her.
They may have burnt her away into nothing if she hadn’t heard a sob somewhere far away. Somewhere in this world of fire, Celestia was dreaming, and remembering that focused Nightmare Moon once more. She knew what she had to do; She opened herself up, let the flames in, let herself fall into the flames. She let the reality of this place wash over it, and as it did the world started to clear.
The flames around her didn’t disappear. If they had, there would be nothing left, because the flames were this place, and Nightmare Moon was starting to see that. Fires wrapped together into shapes, into ground and sky, into trees and grass. Into Canterlot. High above her, the castle warped and swayed with the flames, and that was right.
Then she saw Celestia, shackled to the ground and staring up at the castle.
Nightmare Moon paused. She had to decide how to do this. Her sister needed to listen, she needed to come home, and there was only one way to guarantee that.
So, with a deep breath, Nightmare Moon calmed herself and drew back into Princess Luna.
She walked confidently up to Celestia. “Sister,” was all she said.
Celestia jumped with a start, and her brow furrowed. Her eyes were damp with recent tears. “Of course,” she grumbled. “I should have expected this place to torture me with you as well.”
Luna shook her head. “I am really here, sister. I’ve come to talk.”
Celestia narrowed her eyes. “Why should I believe that?”
With a swipe of her hoof, Luna made the shackles binding Celestia disappear. “I can’t make you believe anything,” she said. “I can only hope you do.”
Celestia studied her for a moment, and then her expression relaxed and she slumped down onto the ground. “Sister, is this really you?”
Luna sat down as well. “I am always me.”
“You know what I mean.”
Luna shook her head. “Nightmare Moon and I are one and the same. I do not exist without her.”
“That’s not true,” Celestia argued. “Whatever she’s made you believe, it’s a lie.”
“I remember everything she does. I know all her thoughts. Even when we were at odds, even when she begged me to take action, I could feel everything she felt. I am Nightmare Moon.”
“I’m not willing to accept that,” Celestia said. “We can do something, we can get you help. Surely Twilight can—”
A hint of anger flashed across Luna’s face. “I do not need ‘help.’ Just because you cannot accept who I am does not mean you can decide I need to be ‘fixed.’”
“Luna, I just want you to be happy.”
“If you want me to be happy, you must allow her to be happy. Who I am is not up for debate!”
Celestia frowned. “Luna, be reasonable. It’s Nightmare Moon, she’s evil! You can’t just let her run your life for you.”
“So I should let you run it instead?” Luna suddenly stood up, and fire flashed through her eyes. “I made one mistake, and you’ve used that ever since to justify your complete unwillingness to treat me as an equal.”
Celestia stood up to match her. “That is completely unfair, you can’t expect me to just never speak up when I think you might be making a mistake. I’m just looking out for you.”
“Why can’t I make mistakes?” Luna swiped a hoof through the end, and bright blue flames erupted from it. “I’m not going to snap and take over the world every time I mess up! I don’t need your protection, I need your respect!” With the last word, she stomped on the ground, and the fire burned up and over her entire body, and when it was gone she was Nightmare Moon again.
Celestia took a step back and grimaced. “How can you say that when Nightmare Moon is standing right in front of me just because you got mad?”
Nightmare Moon took a step forward, and mid-stride changed effortlessly back into Luna. “Because I am not evil! Nightmare Moon helps me to say the things I cannot, the things you have made me too afraid to say. Did you even listen to me before you banished me? I know all the stories about your brilliant heroics say it, so you must have heard. You had a thousand years to improve things, and what did you do? You made me a monster.”
“Luna, that’s—”
Luna swiped her hoof again, and flames wrapped around Celestia’s mouth, snapping it shut.
“Let me speak! You let things grow even worse. Ponies lauded you as their savior, and despised me as the one who would take everything from them. Holidays were made to celebrate my defeat, legends told to inspire fear of me. I became the martyr that lost myself so that you may rise.”
She took another step forward, glaring intensely.
“You could have stopped it! You could have stepped forward at any time and told Equestria about me, not about my singular misstep. And now you treat me like a child, afraid to allow me any freedom and yet so terrified of Nightmare Moon that you elect not to speak to me at all. Equestria sees that! They see your fear of me, your disgust, the way you still blame me for what I did a thousand years later, and they think it’s right! If the hero who saved them thinks I’m still the villain she so bravely vanquished, what are they to believe?”
Luna looked away and shut her eyes tight. Her legs were starting to tremble as she fought to keep the anger in check.
“I’m done,” she decided. “I’ll return tomorrow. I do not intend to abandon you for a thousand years.” Celestia tried to stop her, but the flames around her mouth made her powerless to do anything as Luna turned away, walked a few steps, and then vanished.”
Back in Canterlot Castle, Nightmare Moon had already turned back into Luna before her eyes were even fully open. Distraught, exhausted, and not feeling capable of walking to her bed, she buried her head in her hooves and started to cry.