The story follows Tim Avery (Jamie Kennedy), an aspiring cartoonist whose life changes when his dog, Otis, uncovers the mystical Mask of Loki. After conceiving a child while wearing the mask, Avery finds himself raising a baby ("Alvey") who possesses the chaotic, cartoonish powers of the artifact. Concurrently, the Norse god of mischief, Loki ( Alan Cumming ), is ordered by Odin (Bob Hoskins) to find and retrieve it.