Once hailed as the strongest hitman in history, Taro Sakamoto retired from the underworld after falling in love. After getting married and having a child, he now runs a convenience store—and has put on some weight!
However, Sakamoto is suddenly placed on a bounty of 1 billion yen, and assassins from all sides swarm in. To protect his beloved family and their peaceful everyday life, he must stick to his no-killing code and fight a life-or-death battle against his enemies!