I Saw the Devil

A 2010 South Korean thriller directed by Kim Jee-woon. The film centers on a ruthless serial killer, Jang Kyung-chul (Choi Min-sik), who mercilessly murders a woman, unaware that she was the fiancée of National Intelligence Service agent Kim Soo-hyun (Lee Byung-hun). Driven by grief and an insatiable thirst for revenge, Soo-hyun embarks on a relentless pursuit, not merely to capture the killer but to subject him to a series of torturous ordeals. He tracks down Kyung-chul, beats him to the brink of death, but spares his life, allowing him to experience repeated cycles of pain and terror. This cat-and-mouse game escalates into a series of brutal confrontations, blurring the lines between good and evil. Soo-hyun gradually becomes a monster himself, consumed by vengeance, losing his own humanity in the process. The film delves into themes of revenge, morality, and how the quest for retribution can destroy even the noblest individuals.