A Ultra Beast Pokémon called a Nihilego invaded the world of Canterlot High, and has taken possession of Sunset Shimmer. Arceus sends Ash and his friends from the Alola Region to catch he Pokémon. Meanwhile, the Anon-a-miss event is getting out of control, and Sunset is fully corrupted by the beast. Will the Magic of Friendship be enough to save Sunset from the parasite Pokémon?