Sympathy for Mr. Vengeance tells the story of Ryu (Ha-kyun Shin), a young Korean man who cannot hear or speak, whose sister Han Bo-bae is dangerously ill with kidney disease. Because Ryu and Bo-bae are poor and there is no social system of health coverage in Korea, Bo-bae is not able to receive the transplant she needs to survive. Ryu wants to give his sister one of his own kidneys but he has the wrong blood type. When Ryu is laid off and given a lump sum in severance pay, he seeks out black-market organ transplant. He agrees to give one of his kidneys and ten million won (roughly US $10,000) in exchange for a kidney for his sister. Ryu awakens from anesthesia to find that his kidney has been removed and his money stolen by the black marketeers.
When a kidney becomes available through the hospital, Ryu and his friend Cha-youngmi (Du-na Bae) kidnap the daughter of a wealthy factory owner (Kang-ho Song) in order to raise the money to pay for it. The child dies in an accident and two vengeance plots unfold, that of Ryu punishing the black marketeers and the vengeance that the factory owner wreaks on Ryu and Youngmi for the death of his daughter.
