Kobayashi somehow feels that maybe he can die if he stays with Hanasaki, so he joins the Boy Detectives' Club. His first mission is to help find a jobless young man who's gone missing.

Kobayashi and Inoue are trapped in the underground channels as a result of Twenty Faces' maneuvering. Worried about the officers searching elsewhere in the channels, Inoue tells Kobayashi to escape and warn them that the map they were given is fake.