Renowned private investigator Kogoro, portrayed by Kouta Kusano, is approached by Naoko, played by Yuki Mamiya, with a special request. Naoko, whose family owns a major hospital, seeks Kogoro’s expertise to look into her fiancé, Endo, depicted by Yasushi Fuchikami. She suspects that Endo might be involved in an extramarital relationship with Teruko, a university student played by Noriko Kijima.