Chinomiya Kantaro is an unpopular folklorist in public, but he works as a monster buster secretly. He has been looking for a Tengu that is said to be far stronger than Oni. One day, when he went to exorcize monsters, he finally found the shrine that sealed the "Tengu, the Oni eater", and liberated Shunka. Since then, they've worked together. Although they often have quarrels, their relation began to change solving various problems.