After finding out her husband was cheating on her, a client seeks the help of demon detective Akutabe and his new assistant Rinko Sakuma to make him stop. Akutabe summons Azazel for the task, but he fails two times. To encourage him, he entices Azazel by canceling their contract if he succeeds. He finally does by making the cheater impotent from a suggestion made by Rinko. In the end, Akutabe ends their contract but forces a contract between Rinko and Azazel.
芥辺探偵事務所でバイトをする佐隈は、ある人物からの依頼を受けた芥辺に連れられ、“開かずの部屋”へ足を踏み入れた。そこで目にした芥辺の正体は、悪魔を召喚・使役し、難事件も解決へと導く悪魔探偵だった。芥辺が喚んだのは悪魔アザゼル。事件を解決するよう命じられたアザゼルは、まず佐隈にセクハラを敢行する…！
