Hyeong-do (So Ji-sub) wears a suit and tie like any other rank-and-file white-collar worker... except his profession is a hitman. Seemingly a section chief in the sales division of a metal fabrication company that is actually a front for an organization of hit men, Hyeong-do is regarded as one of the best contract killers in the business and is up for promotion soon. One day, he meets a single mother named Mi-yeon (Lee Mi-yeon) and instantly falls in love. Feeling guilty about his bloody past, Hyeong-do tries to quit the "manufacturer" to the surprise of his colleagues and his enemies. Seen as a loose end, he is immediately hunted down by his former employers.