Daisuke and Kato are ordered by their boss to become partners. They find a pair of comedians performing on the street and suspect that they are involved with drugs. They contact the Metropolitan Police Department about the comedians, but it becomes apparent that Kato and Daisuke have completely different approaches to solving crimes. The kindhearted Kato is disgusted by how Daisuke relies on his wealth to solve problems. They both go their separate ways in the investigation. Kato asks a journalist who he is friends with to help him gather information. While they are on a stakeout, they meet a mysterious woman.

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.