The Moon has fallen, reduced to mere shadow of herself after the Nightmare claimed her. With only fragments of herself left, the Moon must find a way to stop the Nightmare, and escape from her lunar prison. Thankfully she won't have to do it alone.
Twilight Sparkle is embarking on a new path in her life, and Luna is there to guide her to the right one. At long last, it is time for the Stars to come home.
It has been almost a century since Twilight and her friends had discovered their destiny, and Celestia has been wracked with constant regret over the fate she has condemned her friends to. Luna looks to those very ponies to help Celestia smile again.