Upon Princess Luna's banishment to the moon, it was rumored that soul fragments - physical manifestations of the magic used to entrap her - were created. After 50 years since its last sighting, one of the fabled stones resurfaces - in Ponyville, of all places.
The Mane Six soon find themselves in a race against time, forced to retrieve the stone from the dark and chaotic forces attempting to use it to further their own plans.