This comedy-adventure follows Marnie and her younger siblings as they follow their estranged grandmother—a good witch—to her home in Halloweentown, where witches, goblins, vampires and the like lead very normal lives. On her 13th birthday, Marnie learns that she comes from a witch family and that she, too, is a witch. When she discovers that an evil force is plotting to take over Halloweentown, she must help her mother and grandmother save the day.