Tamura is a 46-year-old man with only a middle school education who works at his own pace through temporary jobs. At home, a beautiful wife, a handsome son, and a fluffy family dog await him. His life may not be glamorous, but it is peaceful and fulfilling. Yet Tamura has another identity—he is an exceptionally skilled assassin. As his son reaches adulthood, Tamura decides it's finally time to leave his life of killing behind. However, the boss of the organization has one final and extremely demanding condition before granting his retirement. The legendary assassin father's last mission begins.