In Ikebukuro, a series of phantom slasher incidents by someone wearing rabbit headgear has been occuring.

During that time, Hina Washimiya visits the Inugami Detective Agency run by Eiji Inugami. Hina is the younger sister of Tsukasa Washimiya, who was Inugami’s partner back when he was a police detective. She has the ability to read people’s minds and the thoughts that dwell in objects, and asks Inugami to investigate the phantom slasher case alongside her to uncover the mystery behind her brother’s death.

From there, numerous cases occur and the mystery deepens… and eventually Ikebukuro gets involved—.