When Cho-san was a member of the First Investigation Division 19 years ago, he and Takei were assigned to investigate the murder of Daisuke’s mother, Sayuri. At the time, Cho-san entered the Kambe residence to investigate, and Shigemaru, the head of the Kambe family, surfaced as a suspect in the case. However, the investigative task force folded due to pressure from the top brass of the police, and Cho-san was demoted. Now back to the present, after the mysterious death of Imura, the woman who Daisuke brought into the police station, Kato and Cho-san’s suspicions deepen, so they decide to enter the Kambe residence.