A dude is locked up in a room for 18 years and tries to kill himself constantly. Food is slid under the door and he has no access to outside world except TV.
After 18 years of this hell he is let out of his room and allowed to be free. He goes to a cafe and meets a beautiful young girl (this is all Korean btw) who invites him back to her place (suspicious). He forces himself onto her as he has not seen a woman in 18 years. She runs away but despite this, he calms down and they start a relationship (it was all conditioned/trained into her and setup by main villain).
TURNS OUT IT'S HIS FUCKING DAUGHTER! LOL! Some dude wanted revenge badly, so once the main char impregnated a woman, he got locked up for 18 years, then finds an 18 year old qt3.14 and it ends up his daughter. Tons of fight scenes and raw emotion in movie, 10/10 (for this world).