When Iwanaga Kotoko was eleven, she was kidnapped by yokai who persuaded her to become their "god of wisdom": a mediator between yokai, other supernatural beings, and humans. With the apparently goat-like but also monstrous Sakuragawa Kurou and his ex-fiancée, police officer Yumihara Saki, she attempts to solve a particularly difficult problem. That is, the ghost of idol Nanase Karin, the violent "Steel-Beam Nanase," wanders the streets every night swinging her I-beam at anything that moves. This "ghost" is very likely not what it purports to be.