The film's plot pits a tough loose-cannon cop, Kang Chul-joong, and a psychopathic killer, Cho Kyu-hwan, against each other.

Kang typifies the anti-hero cop genre, taking bribes and stealing drugs from criminals.

Under his cool exterior however, he displays a total disregard for others, killing people for the slightest perceived misdeed.

The two main characters first meet by chance in a dark alley shortly after Cho brutally murders his parents for monetary reasons.

Eventually, Kang discovers a crucial piece of evidence, a broken fingernail, at the murder scene and confronts Cho with it.