Sadie Blake Lucy Liu is a determined reporter who recently published a headline-making piece about a secret Gothic party scene. The night after the piece hits, her source Tricia Rawlins Margo Harshman is invited by her friend Kaitlyn to an isolated house where such a party is planned. Tricia balks at breaking her curfew, so Kaitlyn goes in alone. When Kaitlyn fails to return, Tricia follows. Inside, she finds Kaitlyn in the basement, two vampires hanging onto her and drinking her blood. She tries to hide, but the vampires quickly find her.
The next day, Sadie learns of the girls' deaths and begins to investigate. She soon attracts the interest of the vampire cult, and she is kidnapped, raped and murdered by them. Sadie [Lucy Liu] awakens inside the cold morgue box, realizes she has turned into a vampire, and escapes. She wanders the streets, ending up in a homeless shelter, where she gives in to temptation and drinks the blood of an old sick man. She then runs from the shelter when a young girl notices her, leading her to attempt suicide by jumping off a bridge. Found and later taken in by Arturo [Marilyn Manson], a vampire who is less bloodthirsty and more benevolent than his brethren, she begins to learn to cope with her new condition. His motives are not fully clear—one power struggle with the cult's leader Bishop [James D'Arcy] is hinted at—yet he trains her to fight as she plans revenge on her killers.
Sadie tracks the vampires across the state, slaying them one by one while fighting the urge to feed on human victims. She crosses paths with Detective Clyde Rawlins [Michael Chiklis], Tricia's father, who has decided to avenge his daughter's death despite opposition from his superiors. At first he suspects Sadie, but he soon recognizes she is not like the killers and the pair form an uneasy alliance in pursuit of Bishop, the last survivor. They track him to an abandoned stable complex, where they discover Bishop and Tricia, now a vampire, expressing anger toward her father. A brutal fight erupts as the villains briefly gain the upper hand. Along with two other women, Sadie is stripped naked and suspended by her ankles, wrists bound behind her back, as blood slowly drips. Rawlins arrives just in time to turn the tables.
After Bishop and Tricia are killed, Sadie asks Rawlins to end her life as she cannot bear the thought of surrendering to the bloodthirst and losing contact with her mother and sister. Reluctantly, Rawlins stabs her with a silver crossbow bolt. Once again, Sadie's body falls to the morgue, only to come back to life as the end credits roll.
