A Korean man in China takes an assassination job in South Korea to make money and find his missing wife. But when the job is botched, he is forced to go on the run from the police and the gangsters who paid him.

A serial murderer has brutally killed several policemen and their pregnant wives. After a quick investigation, the murderer is revealed to be Kit, whom the case's detective-in-charge knows from a previous case. Once upon a time, Kit was an innocent boy in a rural village who also has a crush on naïve high school student Wing. After the death of Wing's grandmother, Kit rescues Wing from a foster care facility, and the two quickly fall in love. However, their romance ends prematurely when a local policeman arrests them. The events that follow lay the seeds for Kit's terrifying path to vengeance.