When Princess Luna, turned Nightmare Moon, ravages the kingdom, Princess Celestia has no choice but to banish her to the moon. Regretting her decision, and wanting to make things right, she decides to give Luna some company, with somepony who can appreciate the night sky. None other than Doctor Whooves himself. But time travel can be a sticky business, and the mystery of Nightmare Moon runs deeper than anyone could have thought.
Cover Art done by swanlullaby on Derpibooru