Lewis Barnavelt and his uncle are in England, visiting their cousin at Barnavelt Manor. There, Lewis becomes fast friends with the housekeeper's son. As the two boys explore the garden maze, Lewis accidentally unleashes demonic forces that summon the ghost of Malachiah Pruitt, who tried to have one of Lewis's ancestors executed for witchcraft. Can Lewis fight the manaical wizard, or will all the Barnavelt's perish?