A Wild Namahage.

One day, 300 year-old Namahage is caught in a trap. While being transferred he manages to escape. Wandering through the suburbs of Tokyo, Namahage meets 11-year-old Mamoru and he moves in at the boy's house without Mamoru's mother's knowledge. Mamoru struggles to hide Namahage from his mother. Meanwhile, bad pet shop traders seek out to capture Namahage.