Late on Nightmare Night, after the rest of Ponyville has gone to bed, Pinkie Pie descends into the dark and silent basement of Carousel Boutique. She’s determined to make things better with Rarity after a friendship-splintering fight, but there might not be a solution for the troubles she finds once inside the house. Didn’t anypony tell her it’s not safe to venture out alone at night?

Princess Celestia has been keeping a dark secret from her subjects for a very long time.

It's not an easy truth to tell, but if anyone can accept her after learning it, it will surely be her most faithful student.

Third Place Finisher in Equestria Daily's 2013 Nightmare Night Contest!

On secret assignment from Princess Celestia herself, Twilight investigates a powerful magical artifact for clues to the mystery of Luna's transformation in the evil Nightmare Moon. Incautious use of the artifact sends Twilight hurtling back in time. Can Twilight discover what caused Luna's transformation? And will she ever make it home again?

Kickass cover art used with permission from Bitz.
http://allthebitz.tumblr.com/