Villain: Perpetrator Chase Investigation

Former detective Saeki Shuichi has left the police force and now operates at a private detective agency. One day, a grieving couple hires the agency to locate a man named Sakagami, the killer of their son who had served at a youth detention center. Kogure Masato, the agency's director, directs Shuichi to take on the case. Shuichi is also part of a victim's family—the murder of his older sister occurred during his childhood. As Shuichi shadows Sakagami, the couple asks him to uncover certain materials that could determine whether they can forgive Sakagami or not.