"Sister, wait!" cried Luna, chasing after Celestia. The elder sister did not try to flee, she merely walked slowly across the great hall, her head low and wings dragging on the floor.

When Luna caught up she settled in beside her sister, matching her pace. "What is wrong, sister? Let me help."

The princess of the day shook her head. "I am afraid, Luna, of something our teacher tried to hide from us." she said.

"Starswirl? I'm sure he hid many things. What is it that you have found which worries you so?" Luna nudged her sister's wing until she withdrew them. It would not do to allow her to sully them so.

They were ever so pretty.

The two of them came to the end of the hall. The doors were shut, but Celestia opened them with a word. Beneath them, the stairs descended to the courtyard below where guests had waited the day before as the sun set and the gala neared.

They stopped before descending, Celestia gazing out at the clouds. She closed her eyes and drew out the sun, just enough the paint them with golden lining, her radiant mane rippling.

Luna loved to watch her sister's magic. Celestia was always better at controlling it than she was. A part of her might have been jealous once, but now she held only admiration in its place.

The princess of the night was about to pull the moon from the sky, but Celestia stopped her.

"Let us share the sky for now, sister. It seems only fitting." she said.

Princess Luna was surprised, but smiled and nodded. The two of them sat at the top of the stairs in the morning chill and had their conversation.

"Do you remember the hall of mirrors at the old castle?" asked Celestia.

Luna nodded. "I do. Starswirl was teaching you to scout other worlds found beyond their glass."

Celestia also remembered being reprimanded for making a mean comment to her sister and felt both ashamed and grateful for Starswirl's guidance. She was quite arrogant when she was young, and wondered what might have happened if that arrogance had gone unchecked.

"Once, when I should have been sleeping, I came to the hall to do some exploring on my own." she said.

"My, my, sister. You? A rule-breaker?" teased Luna.

Celestia blushed and nudged her sister's shoulder with her hoof, grinning.

"Anyway..." she continued. "I noticed that once of the mirrors was missing."

Luna raised a brow, intrigued.

"Not only that, but I found broken glass where it should have been." said Celestia. "After that I fled upon hearing hoof-steps, catching a glimpse of our teacher returning to the hall with a broom."

"You think Starswirl smashed the mirror?" asked Luna, shocked.

"I wasn't sure what to think then." said Celestia, "I waited until the next day, then stole a glance at his journal. There was nothing in there about that night, or the day that preceded it."

"Nothing at all?" asked Luna. Their teacher kept notes on everything. It was almost habitual.

"I thought it strange too, then realized that the entry had been torn out." said Celestia.

"Do you think he kept the page?" asked Luna

Celestia shook her head again. "I don't know. He was willing to destroy that portal, wherever it might have led, and say nothing about it. At least, not directly. Perhaps he wanted its entire existence erased from–" She paused, realizing the gravity of what she nearly said. "–memory."

The sisters' minds raced with all sorts of wild scenarios. Questions beginning with 'what if...?' dominated their minds.

"Are some things better off forgotten?" asked Celestia after awhile.

Luna gave it some thought. "I can't say. Sometimes I wish I could forget about being Nightmare Moon, but if I did I might make the same mistakes that brought me down that path in the first place."

There was wisdom in that. How could one learn from their mistakes if they forgot they ever made them?

"There is still more to the story." said Celestia, and Luna nodded her head, ready to listen.

"I checked the next page and found impressions from his quill strokes. Whatever he had written on that page he wrote quickly." said Celestia. "The strokes were too inconsistent to decipher the entry, and what I did find I did not understand. That is, until the curse took you."

"Was it about the nightmare? About what would happen to me?" asked Luna.

"Yes, and no. I saw the word 'nightmare' and 'curse' appear a few times, but your name never came up." Tears began to well up in Celestia's eyes. She looked at her sister, and saw her own eyes widen in understanding.

"But yours did." said Luna.

Celestia nodded. "Several times. I took comfort in knowing the mirror was smashed. Then this human version of you turns up, her body scarred and burned, aware of the nightmare yet not herself cursed."

Luna wrapped her wings around her elder sister, pulling her into a hug and letting her cry on her shoulder. "You didn't give her those scars." she said softly.

"But what if some version of me did?" Celestia countered.

"Her sins are not yours." Luna declared, her confidence bringing Celestia unexpected comfort. "You have faced the nightmare before, multiple times, and never did you become its prey.

"After all that you have done for me, for Twilight and Cadence, Goldilocks and the others, do not doubt yourself. We will find what is hidden, and we will overcome it together."

Celestia's let her heart be lifted by Luna voice. She always was good at giving speeches. It was the small talk she struggled with.

Looking up at her little sister whose gaze was cast heroically upon the horizon, Celestia gave her a peck on the cheek. A blush crept upon the princess of the night, but she remained stoically still as her big sis snuggled up against her.

"Thank you." whispered Celestia.

Author's Note

Wrote this one really quickly. I realize there hasn’t been a lot of sexy stuff since the Gala, but I had a lot of exposition I wanted to get through. Don’t worry though, we’ll soon get back to the real reason you came…