Bad Guy is a South Korean film directed by Kim Ki-duk and released in 2001. The film tells the story of a young woman named Sun-hwa who is studying in college. One day, she is approached by a criminal named Han-gi who is running a brothel. Han-gi becomes obsessed with Sun-hwa and wants her to work for him. When Sun-hwa rejects his advances, Han-gi sets her up by introducing her to a loan shark named Dok-bak.
Sun-hwa borrows money from Dok-bak to pay for her school fees and other expenses. However, she finds it difficult to repay the loan and soon falls behind on her payments. Dok-bak then forces her to work in Han-gi's brothel to pay off her debts. Sun-hwa is initially resistant to the idea but eventually agrees to work in the brothel.
Sun-hwa's life in the brothel is filled with abuse, violence, and humiliation. She is treated as an object and has no control over her life. Han-gi becomes even more obsessed with her and starts to become possessive. Sun-hwa, meanwhile, develops a close relationship with one of the clients, a wealthy businessman.
When Sun-hwa gets the chance to escape from the brothel, she realizes that she cannot return to her former life. She has been deeply scarred by her experiences and has no place in society. She decides to take matters into her own hands and seeks revenge against those who have wronged her.
The film explores themes of power, control, and violence. It portrays the brutal reality of the sex industry and the harm it can do to those who become trapped in it. The film received both critical and commercial success and is considered one of Kim Ki-duk's best works.