The eccentric elderly wizard Depo, fed up with the noisy children on Halloween, decides to summon a terrifying monster using a powerful dark spell recorded in an ancient book and destroy the holiday once and for all.

Due to his dreadful lack of magical talent, however, the summoning goes completely wrong. In place of a fearsome monster appears Gizmo, an adorable little ghost shaped like a soft white rice cake—and an unexpected comedy of chaos begins.