A fourth-grader investigates the mysterious reason behind the sudden appearance of penguins in his village, which is somehow related to a power from a young woman working at a dental clinic.
In the Forest of Okoya, Koko is a feral child who has been raised as a Pokémon by the Mythical Pokémon Zarude. Koko has grown up never doubting that he is a Pokémon even though he can't really use any sort of moves. Ash Ketchum and Pikachu meet Koko and help him protect the Great Tree from the crooked scientist Dr. Zed.
When Keita frees Whisper, a ghost-like yōkai, from 190 years of imprisonment, Whisper pledges to protect Keita from supernatural dangers. Whisper also gives Keita a watch that allows Keita to see other yōkai. Together with the twin-tailed cat spirit Jibanyan, they encounter lots of yōkai-related problems and solve them.
