When Sunset Shimmer returns to Equestria as a pony, she meets new pony Starlight Glimmer and agrees to bring her back through the mirror portal to experience life as a human girl at Canterlot High. However, while Sunset Shimmer is away, a revenge‐seeking Juniper Montage finds a beautiful hand mirror enchanted with Equestrian magic and it’s powerful enough to make things disappear into limbo, trapping them between two realms. Sunset Shimmer and Starlight Glimmer return to find the Mane 6 missing and Juniper Montage acting extremely suspicious. Will Sunset Shimmer and Starlight Glimmer save the girls, or are the Mane 6 lost in limbo for good? (thetvdb.com)