A fantastic adaptation of Émile Zola's Thérèse Raquin. Not that I've ever read any Zola, mind you, but I've read about him. Maybe after I've finished working my way through the entire output of the 19th century Russian realists, I'll be ready. If only Zola had featured more vampires in his stories .... Well, Chan-Wook Park knows how to get me interested in realism, at least -- same as the Russians -- with ideological discussions of atheism.
Sang-hyeon is a Catholic priest with a martyr complex or strong death drive (amounts to the same thing, I suppose), who plays guinea pig in a macabre experiment to help doctors find a cure for a virus that's particularly dangerous to Korean men. He's the only one to survive the voluntary infection, due to a transfusion using vampire blood. The catch is that he now needs to feed on normal human blood to keep from sweating his own and breaking out in disfiguring boils. Initially, he's racked by guilt over his bodily urges, which leads to his sucking on a comatose patient's IV and a fellow priest, Noh, who has a more sanguine attitude about the vampire virus. Sang-hyeon sees vampirism as a loss of humanity, whereas Noh sees it as a gift, and a potential cure for his blindness. Due to his miracle cure, the vampire picks up a religious following of Catholics who see him as another messiah, parallel to that other popular tale of transfiguration. Is he a vampire who walks like a man, or man who acts like a vampire?
Despite the similarities, Thirst doesn't belong to the "vegetarian" vampirism that Buffy made popular and can now be seen in Twilight. It was easy to sympathize with Buffy's beau, because when Angel did evil deeds, it was as the soulless Angelus, who constituted a separate identity (even if the two entities shared the same body and memories, they certainly had no control over what the other did). There's no identity switcheroo in Twilight, but the good vampire Edward is able to survive on animal blood (see 'carouche'). Angel was capable of that, too, having lived on rats for many years after regaining his soul. Furthermore, the two diegeses share a supernaturally enforced Victorian restraint, since the vampires get real thirsty for their lovers when sex is involved. Taking blood and sex out of the equation pretty much makes hash out of vampires, since they're reduced to a more pathetic version of us, but with superpowers. Instead, Park's film is closer in its themes to another vampire show that sometimes gets lumped into the vegetarian subgenre, True Blood.
Maybe because it's on HBO or because it's not written by a Mormon, but True Blood manages to defang the mythology without violating it (although the hamfisted erotic dialog comes close). Here vampires keep their sanguinary sexual desires, are responsible for previous slaughters, and have to choose to live off of synthetic human blood (like only shopping the frozen food aisle). Making a somewhat analogous case to Peter Singer's animal rights argument, Southern gentleman/-vampire Bill Compton has come to view humans as deserving of the same rights as his own kind, since we're capable of the same feelings as he, if not moreso. Whereas True Blood's moral questioning is basically utilitarian, Thirst's is faith-based. The divine image has been transmogrified into a distorted mirror, so is Sang-hyeon still obligated to God's favored creature? If the vampire is nothing more than pure carnality, then its moral status is that of all the other animals not given the lead in the story of Eden. Scorpions aren't being immoral when they strike.
Thirst's vampiric version of the 19th century nihilist is Tae-joo, an orphaned girl who came under the care of the domineering Lady Ra and her spoiled, sickly boy, Kang-woo. Rather than being raised as the boy's adopted sister, Tae-joo became his caretaker and wife. Sang-hyeon was a childhood friend to the family and, post-transformation, meets up with them again when Ra comes begging for a miracle to cure her son. Between games of mah-jongg with the family and friends, the priest and the wife begin to slip away for bouts of hedonism that's erotic in a way the metalhead couple making out in a mall could appreciate. Based on how she grew up, Tae-joo doesn't see much that's special in humanity, so wants nothing more than to leave it all behind by being turned. After a series of sinful events, including the plan to kill Kang-woo, Sang-hyeon grants her the salvation she desires. That's when he discovers that some vampires are more Darwinian than others. She's pure survival-of-the-fittest with nothing filling up the hole of faith. Humans are reduced to the status of actors -- that is, cattle -- and she's the only director that matters. Feeling himself drawn to the abyss, with his monstrous status of being nothing but an animal, only with the ungodly power to upset the divine heirarchy, Sang-hyeon can see no other moral choice than self-immolation -- and, thus, the movie's central conflict. Obviously, the couple hasn't read much utilitarianism or other atheistic moral philosophies. They might've discovered with Bill that there's more of a connection to humanity than the forced choice between nihilism and theistic middle-management allows.