In Salem, Massachusetts in the late 17th-century, three evil witches - Winifred, Sarah and Mary Sanderson - take the lifeforce out of little Emily Binx and turn her brother Thackery into an immortal black cat, for which anti-social behaviour they are duly hanged. However, before they die, they prophesy that if a virgin should light their black-flamed candle, they will return. Three hundred years later, teenager Max moves from Salem to Los Angeles. Max has no time for Halloween which was, he says, invented by sweet manufacturers to boost their sales. However, his little sister Dani insists he accompany her trick-or-treating. While they are out, Max bumps into classmate Allison and, wanting to impress her, convinces her to accompany him to the Sandersons' house, which is now a museum. While there, he lights the black-flamed candle and the witches return, determined to steal more life-force from children so they can live forever. With the help of Binx the cat, the kids steal the witches' spellbook and escape, pursued by the sisters, who must get the book back and get more lifeforce before sunrise, or they'll turn to dust.