All the youth of Mewni gather at the ancient Monster Temple to celebrate a new era of Monsters and Mewmans living together in peace, until guests start disappearing!.
After having skirmished with a number of dangerous monsters, Star Butterfly arrives on Earth to live with the Diaz family. However, rather than living a normal life, Star continues on having to battle villains both throughout the universe and in their high school, although if only to protect her extremely powerful wand, an object which she is still confused with.