Dae-su's captor is revealed to be a wealthy man named Lee Woo-jin. Woo-jin gives him an ultimatum: if Dae-su can uncover the motive for his imprisonment within five days, Woo-jin will kill himself. Otherwise, he will kill Mi-do. Dae-su and Mi-do get close and have sex. Meanwhile, Joo-hwan tries to contact Dae-su with important information but is murdered by Woo-jin. Dae-su eventually recalls that he and Woo-jin had gone to the same high school, and he had witnessed Woo-jin committing incest with his own sister. He told Joo-hwan what he had seen, which led to his classmates learning about it. Rumors spread and Woo-jin's sister killed herself, leading a grief-stricken Woo-jin to seek revenge. In present day, Woo-jin cuts off Mr. Park's hand, causing Mr. Park and his gang to join forces with Dae-su. Dae-su leaves Mi-do with Mr. Park and sets out to face Woo-jin.