Imagine finding out you some from a family of witches. Trippy, right? Well, that's what happens when 13-year-old Marnie Piper (Kimberly J. Brown) discovers she and her siblings Dylan (Joey Zimmerman) and Sophie (Emily Roeske) are part of a sorcerous bloodline. After secretly following their grandmother, Aggie (Debbie Reynolds), onto a magical bus, the three children find themselves in the world of Halloweentown. Soon after, Aggie begins training Marnie in the art of magic, which comes in handy when an evil force threatens to take over the world.