I Saw the Devil

I Saw the Devil: Kyung-chul, a dangerous psychopath who kills for pleasure, has committed horrifying and senselessly cruel serial murders on defenseless victims. One day, Joo-yeon, daughter of a retired police chief becomes his prey and is found dead in a horrific state. Her fiancé Soo-hyun, a top secret agent, decides to track down the murderer himself.