Star Butterfly is a princess of the magical dimension of Mewni that when completing 14 years gains like birthday gift of its parents a powerful magic wand that for generations belongs Butterfly family, in addition to a book of spells that contains all the spells created by the old owners of the wand. But Star can not properly control the powers of her wand, so she is sent immediately to Earth, a safe place where she can practice. Still on Earth, she meets Marco Diaz, who becomes her best friend.