Toru Shirakawa

Not long after twin brothers Ryuichi and Ryuji were born, they were abandoned by their own parents. They were then adopted by the Yoshie couple, who ran a small shipping company. Sometime later, the Yoshies gave birth to their daughter Misa. Ryuichi and Ryuji enjoyed pleasant days with their adopted parents and younger sister Misa. When Ryuichi and Ryuji were 15-years-old, their parents experienced extremely dark days because of Genpei Kirishima, who ran a competing shipping company.

Detective Seiichiro Watari is nearing retirement, but is still bothered by an unsolved case from seven years ago when the decomposed corpse of a female was found by a fisherman in the sea of Otaru. The body was never identified so the case was never solved. Three years after his retirement, Watari unexpectedly discovers a clue that may finally solve the case.