I Saw the Devil is a 2010 South Korean psychological thriller/horror film directed by Kim Jee-woon, written by Park Hoon-jung, and starring Lee Byung-hun and Choi Min-sik. The film introduces the character of NIS agent Kim Soo-hyun (Lee Byung-hun), who embarks on a quest of revenge when his fiancée is brutally murdered by a psychopathic murderer, Jang Kyung-chul (Choi Min-sik). The line between good and evil begins to blur when the two play a dangerous game of cat and mouse. I Saw the Devil made its premiere in the United States at the 2011 Sundance Film Festival and had a limited U.S theatrical release. The film was Choi Min-sik's first major role since the changes to the Korean screen quota system. It has received generally positive reviews with praise towards the acting, direction, cinematography and script.