Single father Kenichi has raised his daughter Miki alone for the past ten years, from when she attended nursery school until her graduation from elementary school. Kenichi is currently 30 years old. His wife Tomoko died at a young age and he has raised Miki alone since that time. While raising his daughter alone, he has encountered various problems.

An island in Japan is the site for the dumped and the refuse. Nanakusa and Yu who were childhood and school friends meet on this island that is called Kaiden, a scary name that only refers to things not normal or earthly. The reunited friends strike a bargain and are soon involved in cases most would not dare be involved in or become entangled in.