Nightmare was chained. Her forelegs pulled over her head as her hindlegs were standing on the ground, her back to the wall. Her wings were bound equally and her horn still had the accursed ring perched on top of it.

That is how they left her. Helpless with her private bits like her teats and marehood on full display.

She assumed Celestia didn’t really care for the decency of her prisoners. Still a bit surprising, coming from that prude cunt. But alas she assumed that this was more about keeping her prisoners as helpless as she could, instead of humiliating them.

Nightmare in any case didn’t really mind to have her goods on show for the guards.

Not that there were any that stared. Only one guard was stationed in front of her cell, and that one didn’t move, no matter how many muffled sounds she produced through the muzzle they had strapped to her mouth.

Maybe that was because the only time he looked she had spread her hind legs and thrust her hips forward.

That guard blushed furiously and berated her before simply giving up and opting to ignore her.

‘It was always fun to tease the guards. Even back then. Albeit I had to be more subtle about it lest that wretched sister of mine would ruin my fun. Just like she always did.’

It was in that moment that her ears twitched as she heard the telltale signs of clopping hooves on stone nearing her cell.

“Princess!” the guard greeted, no doubt bowing his head to this foul being that was gracing Nightmare with her presence.

“At ease. I hope she didn’t cause you any trouble?” Celestia asked, still out of sight.

“N-No. At least nothing too much,” the guard stammered and Nightmare imagined he probably turned his head away blushing, making her grin slightly.

A sigh from the white alicorn mare followed as she nodded to the guard.

“Not like I expected anything different from her,” she mumbled before finally trotting to the cell.

Her fur and mane were impeccable as always, though Nightmare assumed that she probably took a bath. She also wore her regalia, trying to emit an air of authority as she opened the cell door and stepped in without any hint of hesitation or fear. She had a book floating alongside her.

‘Mastery of Balance: Reformation Spells and their Application,’ Nightmare read the title and couldn’t help but chuckle.

“What is so funny, Nightmare? Any more twisted jokes you would like to pull?” Celestia asked her with clear disdain. She then pulled the muzzle off of her with magic and set it down on the cold stone floor so she could answer.

“Isn’t it obvious? Your desperate attempts to find a spell to purge me? To force balance, without even realizing that I am balance itself? I am the balance Luna needed. That you wouldn’t give to her.”

Celestia used her magic to bitchslap Nightmare’s left cheek, a snarl on her face, “Don’t you DARE speak that name!”

While that hit stung, Nightmare still managed to maintain a grin.

“The truth hurts, doesn’t it? She needed her sister to support her in her dark hours, but as she didn’t get the support it was up to me. Up to me to show her the fun side of life,” Nightmare purred.

Celestia’s face twisted into a mask of rage, but she quickly pushed those feelings down, trying to not let this monster get under her skin. Instead she opened the book to a bookmarked page.

“Say what you will, but in the end you won’t exist for much longer.”

As she finished that sentence her horn started to glow. A glow that got brighter and brighter until it enveloped Nightmare Moon. Said mare could feel her dark fur stand on end and she started to grunt.

Celestia poured more of her magic into it, seeing that as a good sign as she let the weaved spell matrix wash over her, fixing her sister and completely cutting Nightmare from her, once and for all.

The light was blinding at this point and Celestia felt some exhaustion herself with how much she was pouring into this, just to make sure every last speck of Nightmare’s darkness would vanish.

Then the white mares legs collapsed under her as the spell was completed, the blinding light slowly receded, leaving the cell as it once was. With one change.

Celestia looked up, her eyes hopeful. They widened as they saw what was before her. A slightly smaller bound form with dark blue fur. No wicked teeth, no slit eyes.

Tears welled up in Celestia’s eyes as she saw this, the book dropping from her magic and on the floor with a resounding thump. She teared up even more as she heard the sweet voice of her sister for the first time in a millennia.

“T-Tia?” the voice quivered and Celestia smiled brightly. She stood up, instantly hobbling over to her and giving the mare a fierce hug, nuzzling her lunar sisters cheek.

“Y-Yes Luna. It is me. I’m here. I’m here for you,” the alicorn of the sun whispered, trying to contain a few happy sobs.

As she finished her nuzzles her eyes went to her face, muzzles close as she smiled happily at her. Probably the happiest she has been for a thousand years.

Then suddenly her sister for some reason smirked. It confused Celestia greatly.

And then she pressed her muzzle onto hers.

Celestia gasped in surprise, which turned out to be a grave mistake as it allowed the lunar princess to sink her tongue into the white mare’s muzzle, said tongue sweeping over the inside of her mouth naughtily.

It took Celestia a moment to shake off her shock and pull away. A thin line of spit connecting their lips for a moment.

“W-WHAT THE BUCK LUNA!” Celestia screeched with hotly flushed cheeks.

Said mare just giggled. Her head lowered so that Celestia couldn’t see her eyes.

“Y-You should see the look on your face bwahahaha!” the mare laughed boisterously before lifting her head and a pair of turquoise slit eyes stared back at her.

The mare smirked as Celestia stepped back, her eyes turning to pinpricks.

“No…”

“Yesssssss!” the darker mare hissed as her teeth sharpened and her fur turned from dark blue to black, starting from her muzzle.

The white alicorn’s heart sank, but at the same time she felt her rage boil up again. She glared at Nightmare as she started to guffaw out a laugh again, clearly in high spirits from her cruel prank.

Celestia for one had no words. There were no words in her mind to express the anger she felt. The utter hatred towards this being that was toying with her, mocking her.

She screeched out, an ungodly noise as she stomped on the ground. It cracked, instantly creating a crater and going as far as to crack the walls surrounding them.

Celestia panted afterwards, sweat dropping from her brow as one could hear the cell crumbling around them.

It took everything in her not to unleash this on Nightmare herself, lest she kills her own sister in a fit of rage.

Still, while it calmed her, it didn’t satisfy her nearly enough. Frustration, anger, sadness. All was mixed into her being. There was no happiness to be gleaned in her situation. Not until she would resolve this. Not until she had her sister back.

So she lifted her head, looking at the Nightmare as determined as she could.

And the Nightmare just smiled back.

Celestia waited for it. Waited for another teasing remark. Waited for her to insinuate that she needs some stallion to relieve her stress. But she didn’t. She didn’t need to.

The Nightmare was well aware that she had won this round. There were no words needed to affirm that. And any comments would just cheapen this victory.

Celestia then turned around and walked out of the cell.

She looked at the frightened guard and already saw more coming down from the hall, clearly having heard her outrage. Leading them was none other than their Captain, Shining Armor.

He halted in front of her, saluting.

“Princess, we have heard a commotion and came as quickly as we came to support you.”

Celestia sighed, she’d rather not have them see her sign of weakness, but she hardly could hide it.

“It is quite alright Captain. I was just...having slight troubles with the Nightmare. She can be quite provoking. Anyway, she will need a new cell. I trust you can take care of this?”

The unicorn bowed his head, “Of course, your majesty. It will be done.”

Celestia nodded and gracefully walked past the guards, leaving them to it. Her magic flared up as she quickly levitated the book out of the cell that she had dropped prior. It was in a poor state, but nothing a simple spell couldn’t fix.

For now she would have to visit her student. Her research for a suitable spell obviously failed and she would have to reprimand her.

The thought alone made her sigh again.

‘Maybe I should have kept Sunset.’

Author's Note

My Editor pointed out that Nightmare technically could have let go of the kissing prank and instead could have tried to get free with her act of being Luna. A short explanation to that. Celestia would have checked her over still before freeing her of her restraints and noticed that something was off, discovering it.

At least that is the explanation I would give, in case anyone wondered.