The film begins with 13-year-old Marnie Piper (Kimberly J. Brown) and her mother, Gwen (Judith Hoag), arguing over why she and her younger siblings 12-year-old Dylan (Joey Zimmerman) and 7-year-old Sophie (Emily Roeske) can never go out for Halloween, and why Marnie cannot go to a Halloween party. Her mom offers no clear explanation. Gwen's mother Aggie (Debbie Reynolds), who is an expert witch, shows up for her annual Halloween visit. The children are happier to see Aggie than Gwen is, as Aggie openly encourages the children to get more involved in Halloween.
Every DCOM ever aired... minus the commercials.
On Halloween night, three siblings — Marnie, Dylan, and Sophie — learn that their grandmother, Agatha Cromwell, is actually a witch living in Halloweentown, a community where spooky beings have separated themselves from Earth's history to escape humans' fear and persecution.