In April 1905, a group of fashionable Parisian women arrive at an abattoir to drink the blood of an ox as a way to cure anemia, and find the result successful.
Meanwhile, after a successful robbery, Marc, the young leader of a gang of thieves, betrays his four accomplices as he plans to escape to London with the gold coins they have stolen. Chased by his former accomplices, he flees to the countryside and takes refuge in an isolated château inhabited only by two bisexual chambermaids, Elisabeth and Eva, who are awaiting the arrival of the Marchioness and her servants. The women, who appear to be in a romantic relationship, are amused by Marc's presence and assure him they will not turn him in to the police.
Eva offers herself to Marc, and the two have sex, sparking Elisabeth's jealousy.
Marc's former accomplices discover his hideout, and a shootout ensues at the château. When Eva goes outside to hand over the gold, the thieves take her to the stables; while two of them count the gold coins, the new leader of the gang forces Eva to give her dress to her wife. The leader then coerces Eva into sex, whereupon she stabs him to death. Armed with a scythe, Eva kills the remaining thieves before calmly returning to the château. Elisabeth tells Marc he can escape before nightfall, but he decides to stay.
That evening, the Marchioness arrives with her servants, and they hold a party in which Marc is the only man, so he gets all the attention. At midnight, the women change into transparent robes, supposedly for a secret ceremony. Since he is still on the run, Marc flees into the stables, looking for a horse he can use to escape. Eva is sent after Marc to bring him back to the château, but Elisabeth intervenes by shooting Eva. Elisabeth and Marc flee while a wounded Eva crawls back to the château, where the servants drain her blood.
In a nearby pigeon loft, Elisabeth explains to Marc that she, Eva and their guests were prescribed ox blood by a doctor as a cure for anemia. However, the women acquired a taste for blood and decided to feast on human blood. They subsequently formed a secret society, luring young men into the château and drinking their blood. Elisabeth admits that she never loved Marc and shoots him dead before tasting his blood. She returns to the château and lies to the Marchioness, claiming that she killed Marc after he killed Eva. The Marchioness tells Elisabeth that she looks beautiful with Marc's blood on her lips.
