Thirst (2009)

Catholic priest Sang-hyun volunteers for an experiment to find a vaccine for the deadly Emmanuel Virus. He becomes infected, but recovers after a blood transfusion. His congregation believes he can heal, and crowds come to see him. Among them is his childhood friend Kang-woo, who invites him to the family's weekly mahjong nights, where Sang-hyun is drawn to Kang-woo's wife, Tae-ju.

Sang-hyun falls ill again and wakes up as a vampire, needing blood and fearing sunlight. He tries to kill himself, but cannot resist blood, so he steals it from the hospital and drinks from a coma patient. He begins an affair with Tae-ju. When she learns what he is, she is frightened, then suggests they kill her husband.

Sang-hyun sees bruises on Tae-ju, and she claims Kang-woo beats her. During a fishing trip, Sang-hyun drowns Kang-woo. Mrs Ra, Kang-woo's mother, collapses into a paralysed state. Sang-hyun and Tae-ju are haunted by visions of Kang-woo's corpse. When Tae-ju admits that Kang-woo never hurt her, Sang-hyun is furious. She asks him to kill her. He does, but cannot bear being alone, so he feeds her his blood, and she wakes as a vampire.

Tae-ju kills without remorse, while Sang-hyun only kills when he must. Mrs Ra manages to tell Kang-woo's friends that the pair killed her son, and Tae-ju murders two of them. Sang-hyun pretends to kill the third to protect her. He then makes his followers believe he is a sinner, so they stop worshipping him.

Sang-hyun drives Tae-ju and Mrs Ra to an open field before dawn. Tae-ju realises his plan and tries to hide, but he stops her every time. At last she gives in and sits beside him on the car bonnet. They burn to ash in the rising sun, as Mrs Ra watches from the back seat.

Why does Sang-hyun drive into the sunlight? He knows Tae-ju will keep killing, and that he cannot stop her any other way. He chooses to end both their lives.

Why does Tae-ju give in? After failing to escape, she accepts her fate and sits beside him, a final moment of love between them.

Why does Mrs Ra watch? She is paralysed and cannot speak, but she witnesses the death of her son's killers, a cruel kind of justice.

Why does Sang-hyun pretend to be a sinner? He wants to end his followers' worship, so they will not idolise a murderer.

What is the story based on? Émile Zola's Thérèse Raquin, in which lovers murder the woman's husband and are destroyed by guilt.