Professor Himeda, who teaches folklore at the university, has launched a youkai circle. At the end of the Edo period, a demon woman who fell in love with a kappa and a zashikiwarashi tried to trick the villagers into breaking up their relationship, but the kappa, with the help of a high-ranking priest, sealed the demon in a mound. Himeda wanted to find the "mound". By chance, he hears that member Asano is from the birthplace of yokai legends and that her family runs a guest house, so Himeda heads to a research camp with other members Satomi (Riri Kuribayashi) and Shibata. However, Shibata is shocked when she learns that Satomi, who had been in love with her, is actually having an affair with Himeda. On the other hand, Asano, who has returned to his parents' house ahead of others, waits for the arrival of the party with Mr. and Mrs. Nagata, who run a guest house, and his daughter Aya (Ito Kurenai).