From famed thriller director Ji-woon Kim comes this edgy thriller about secret agent Dae-hoon (Byung-hun Lee), who discovers how far over the edge he will go in order to seek revenge after his fiancée is brutally slain by psychopathic serial killer Kyung-chul (Min-sik Choi). With the police baffled by Kyung-chul's murders, Dae-hoon decides to capture the killer, but his own increasing violence makes him wonder who the monster really is.