Everyone at Sweet Valley Middle School has always said the Mercandy mansion is haunted. Strange lights flicker in the windows at night, and no one ever sees the owners come and go. So when Nora Mercandy moves into the run-down house, rumors spread fast. Jessica Wakefield and her friends are convinced that Nora is a witch. But Elizabeth, Jessica's identical twin, is certain that Nora is just an ordinary girl. She's determined to stick up for her new friend. She'll get to the bottom of the mystery of the Mercandy Mansion—even if it means losing her sister's friendship.