Twilight has been given the opportunity to study under Star Swirl the Bearded. But... how is it even possible? And how did nopony realize who she really was?
After a particularly rough day, Twilight accidentally activates a spell she read earlier but didn't understand. She wakes up the next morning in darkness. Her only chance is to find Princess Celestia to return Equestria to how it is supposed to be.
Decades after Sunset Shimmer reunites with Princess Celestia during the events of "Forgotten Friendship", she recounts what was both her most anticipated moment and her most feared.
A thousand years ago, Princess Luna becomes overcome with negative emotions, and one day finds herself unable to control her own body. Her mind intact, she has to deal with whatever's taken control of her.