Ashibe-kun wanted to gather chestnuts, so his grandpa bought a mountain for him! Goma-chan has never had chestnuts before, so he`s excited, too! Now, let`s all go pick up chestnuts together! The gang searches the ground in a grove of chestnut trees, but... what? There are no chestnuts anywhere. Then they find some mysterious footprints... Could the one who ate all the chestnuts be the unidentified creature Cheskenstein?!