Jinpei Matsuda was originally a member of the Tokyo Police bomb squadron. His partner Kenji Hagiwara was killed four years previously by a serial bomber in Shinjuku and he had sworn revenge on the police for the accidental death of his partner. When the killer resurfaced three years ago, Matsuda's superiors, fearing that he would become reckless due to personal interest, transferred him to Megure's department, where he was promptly partnered with Miwako Sato, then a rather new detective.
