I Saw the Devil is a 2010 South Korean horror thriller directed by Kim Jee-woon. The film features a relentless cat-and-mouse game between a skilled secret agent and a sadistic serial killer who murders the agent's fiancee. As the agent seeks revenge, he blurs the lines between good and evil. It stars Lee Byung-hun as the vengeful agent and Choi Min-sik as the ruthless killer. Critics generally liked the movie, particularly horror fans.
(Summary by FreeGreatMovies.com)