Equestria, a land of magic and bending, has lived in peace for centuries. For centuries it was protected by the cycle of Avatars, but when the avatar disappeared, two ponies took it upon themselves to defend their home. They were Celestia and Luna, the alicorns sisters. Equestria was restored under the newly-named Princesses' wisdom and guidance... until that fateful night.

Sunset Shimmer, student to Princess Celestia, is sent forward in time to stop Nightmare Moon. On her arrival, she meets a noblemare named Twilight Sparkle, and her dragon assistant Spike. With her two new companions, she ventures on a journey to stop Equestria’s new queen and free Princess Celestia. As they travel, they learn that they also have to find the answer to a centuries-old question:

What happened to the avatar?