Kurayukaba

Rumors spread through the city about mass disappearances that leave no witnesses and no clear explanation, only mysterious tracks appearing near the places people vanished. Detective Soutarou takes the case and realizes that searching the surface will lead nowhere, forcing him into Kuragari, the hidden underground world beneath the city.

Among smoke-filled tunnels he encounters a black armored train commanded by Tanne, a woman who clearly knows more about this realm than she says. Their investigation moves through secret networks and conflicts invisible to the city above. The closer Soutarou gets to the missing people, the clearer it becomes that the case is not only about those who disappeared, but about an entire world living under everyone's feet.