The name Tarou Sakamoto once instilled fear in every villain. No other professional hitman matched his prowess, and fellow assassins revered him. However, Sakamoto fell in love. In five short years, he married, became a father, put on some weight, and traded his weapons for an apron as he became the owner of a humble convenience store.

Although Sakamoto is decidedly retired, he finds his old life of crime hard to shake off. His former partner, Shin Asakura, reappears and resolves to stay with Sakamoto's family under their strict no-kill rule. To make matters worse, a large bounty is placed on Sakamoto's head. Numerous assassins now pursue him—but they are in for a surprise. Sakamoto has not lost his edge, and no matter what tricks his enemies pull, he will fight off every last one to protect his dear family.