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.

Star returns to her home dimension of Mewni where she discovers that magic is disappearing throughout the kingdom; Star must dig deep and challenge archnemesis Ludo in an effort to save her family and kingdom.