This reminds me of a scene at the end of Chapter 8 of Gettin g Even by Mint. www.fimfiction.net/story/19647…

Twilight walked up the steps of the building, nervously anticipating reaching the top. Luna would be up there. Would Twilight have another strange reaction like that again? Twilight wasn’t sure if she could even walk when her body completely locked up like that. With a very nervous last step the unicorn arrived at the tower’s balcony. What she saw surprised her.

For a brief moment, Twilight felt terror. A familiar pony was sitting at the balcony, but not the one she was expecting. Her hair flowed like mist and her mane was as dark as the night sky.

‘Nightmare Moon!’ Twilight thought. She was preparing to turn and run or panic or try to calm the powerful pony down...but something stopped her. The alicorn wasn’t doing anything. She was simply sitting on the balcony, staring down at the ponies on the ground and then back up at the floating lanterns. Luna’s voice played in Twilight’s mind.

“That part of me was happy to be free...because she was lonely.”

Now there were countless ponies on the ground, admiring the night, the very lack thereof that made Luna create Nightmare Moon. Luna wanted her to enjoy this too. There was only one thing left that would make it perfect. Twilight fearlessly trotted over to her. She sat beside the large alicorn. Nightmare Moon turned and saw who it was and returned her gaze to the lanterns in the sky.

“Twilight.” The alicorn said casually.

“Lovely night.” Twilight replied.

“Lovely night indeed.” Nightmare Moon’s face appeared mellow somehow. Her usual grimace lacked its angry intensity. Twilight gazed up at her. There was a twinkle in the terrifying pony’s eyes, one that the unicorn was sure wasn’t there before. The lavender pony leaned against Nightmare Moon affectionately, causing the alicorn to give her an odd look.

“Are you happy?” Twilight asked.

“About what?” Nightmare Moon retorted.

“Everypony’s appreciating the night now. They’re all looking at it, counting the stars and celebrating with lanterns.”

“About damn time.” Nightmare Moon said, gazing back out at the crowd.

“I’ll take that as a “yes.”” Twilight said, rubbing against the alicorn’s large shoulder. Neither of them spoke after that. Neither of them had to.