Canterlot has experienced many disappearances, from teens to adults. The only thing known about these disappearances is that they occur after a duel with strange lights in the sky. But some people do return, but they are changed in some way.

Sunset and the girls believe that Equestrian magic is behind the disappearances. They decide to go out and find the perpetrators themselves. But going alone is a terrible idea, so they need help from a new friend with some unknown abilities. Can this group put a stop to the disappearances before one of their own is taken? Who is behind all of this?