The ventriloquist Tengan puts on a show about a ventriloquist who becomes possessed by his doll and murders his wife. Tengan falls victim to a genuine split personality disorder, and the personality of his doll appears and orders him to kill his wife Kazuko. The next morning, Kazuko is found murdered. Tengan confesses...

Conan, Ran, Kogoro, Heiji, and Kazuka visit an inn deep in the mountains of Nagano. Heiji acquires a photo of a figure carrying a scythe running across the surface of the outdoor bath. Conan and his friends have come to investigate the true identity of this figure who resembles a Kamaitachi.