On her 13th birthday, Marnie (Kimberly J. Brown) learns that she comes from a family of witches and that she too is a witch. Soon she and her younger siblings return with their estranged grandmother, a good witch (Debbie Reynolds), to her home in Halloweentown, where witches, goblins, and vampires lead normal lives. Marnie soon discovers that an evil force is plotting to take over Halloweentown, and she must help her mother and grandmother to save the day.
Grandmother Aggie (Debbie Reynolds) sweeps Marnie (Kimberly J. Brown) and Sophie (Emily Roeske) off to Halloweentown to investigate a series of strange occurrences. When they arrive, the vibrant community seems to have lost its magic. It isn't long before Aggie discovers that her spell book is stolen and the trio must find it. They discover that an angry warlock has taken the book and plans to permanently turn every human into whatever costume they are wearing on Halloween.
A portal has been opened between the human world and Halloweentown and Marnie (Kimberly J. Brown) sets up an exchange program to bring a group of Halloweentown students to attend her human high school. When she inadvertently bets the Cromwell magic that no harm will come to the students, strange things start happening! Marnie and her family must get to the bottom of things and protect the students from the legendary Knights of the Iron Dagger - and save their own powers.
Against her mother's wishes Marnie (Sara Paxton) goes to college at Halloweentown's Witch U. But things aren't easy at Witch U as magic is forbidden on campus and an ancient prophecy makes Marnie the target of an evil conspiracy!
