A Jonan Station detective, Kikuchi, is framed for a murder and sent to prison. When he is paroled, he joins a private detective agency, where he is asked to investigate Mitsue Takazawa, the wife of a local trading firm president. While secretly conducting his own research, he finds out that Takazawa's husband is the one, responsible for Kikuchi's imprisonment, who also have set sights on Setsuko, a woman Kikuchi becomes romantically involved with.