Sympathy for Mr. Vengeance

Ryu is a deaf-mute man who works in a factory. His ailing sister is in desperate need of a kidney transplant, but Ryu's is not a match. After he loses his job, Ryu contacts a group of black market organ dealers to exchange one of his kidneys for one that his sister can use. However, the dealers disappear after taking Ryu's kidney and severance money.

A legitimate kidney donor is found, but after having been conned by the organ dealers, Ryu is unable to afford the operation. To raise money, Yeong-mi, Ryu's radical anarchist girlfriend, suggests kidnapping the daughter of the executive that fired Ryu. They observe the executive with company president Park Dong-jin arriving at the latter's home one day, where one of Dong-jin's employees, Peng, attempts to commit harakiri in front of them. Ryu and Yeong-mi change their plan, deciding to kidnap Dong-jin's young daughter Yu-sun.

Yu-sun stays with Ryu's sister, who believes that Ryu is babysitting her. Ryu and Yeong-mi send a request for ransom to Dong-jin, and he obliges. Upon returning home with the ransom money, Ryu discovers that his sister learned that Yu-sun was kidnapped and not wanting to be a burden any longer, has committed suicide.

Ryu takes Yu-sun and his sister's body to a riverbed they frequented as children to bury her. Distracted by the burial and unable to hear, Ryu is unaware when Yu-sun slips into the river, and she drowns. After Yu-sun's body is discovered by authorities, a deeply mournful Dong-jin hires an investigator to find her kidnappers. Dong-jin finds Ryu's sister's corpse by the riverbed, interacts with a mentally disabled man who witnessed Ryu burying his sister, and begins to piece together the identities of Ryu and Yeong-mi.

Ryu, armed with a baseball bat, locates the organ traffickers and murders them, receiving a stab wound in the process. Meanwhile, Dong-jin finds Yeong-mi and tortures her with electricity, also killing a deliveryman who comes to her apartment. She apologizes for Yu-sun's death but warns Dong-jin that her terrorist friends will kill him if she dies. Unfazed, Dong-jin electrocutes her to death. Ryu returns to Yeong-mi's apartment and sees the police removing her corpse.

Dong-jin knocks Ryu unconscious with a booby trap. He takes Ryu to the riverbed where his daughter died and drags him into the water. Dong-jin slashes Ryu's Achilles tendon and waits for him to drown. After Dong-jin dismembers Ryu's corpse, Yeong-mi's anarchist associates arrive. They stab Dong-jin, pin a note to his chest with a knife, and leave him to die.