The work is based on many of the famous Japanese mystery novelist Edogawa Ranpo's works, combining Ranpo's fantasy worldview with the modern stage. The animation tells the story of a teacher being killed in a middle school. Kobayashi, a boy who attends this school, meets the genius detective Akechi who comes to investigate the case. Kobayashi is interested in Akechi, who only investigates abnormal crimes, and volunteers to become his "assistant" despite the opposition of his friend Hashiba. In the strange incidents that happened one after another, Kobayashi and Akechi quickly started investigating.