An eclipse of a full moon awakens Sadie, an elderly African American woman. In a swamp, a creature rises from muck and transforms into “Lilith,” a beautiful woman. In the morning, a radio announcer mentions a rash of violent crimes and crib deaths in maternity wards. At the editorial office of Siren, a fashion magazine, staffers Rod and Craig discuss how to present a photograph of a woman on the cover. Kenny, the office “nerd,” mentions a dream he had last night, and Craig for a moment recalls his own dream of a beautiful woman rising from murky water. Lilith drives Siren publisher Joseph Crenshaw home and tells him his wife is waiting inside. Crenshaw asks how she knows his marital status and where he lives. Lilith slips his gold ring back on his wedding finger, and he gives her his business card. Lilith asks Crenshaw to put her photograph on the cover of his magazine. He tries to kiss her, but Lilith shoves him out of the car, tosses his card on the road, and drives away. As Crenshaw prepares to climb into bed with his sleeping wife, a breeze blows outside, where a llama eats grass. Lilith is suddenly in the room, seducing Crenshaw next to his wife. Slashing him with her long fingernails, Lilith tastes his blood. When Mrs. Crenshaw awakens, Lilith cuts her throat and smears Joseph Crenshaw with her blood. Elsewhere, Craig awakens from a nightmare. Later, at the Siren office, Rita, the editorial director, announces that Joseph Crenshaw, his wife, and son were murdered last night. However, the editorial staff will hurry to complete the next issue, and the magazine party will be held as scheduled because the largest advertisers have already flown into town. That night, the party is lightly attended. Craig, Rod, and Ken are there. Rita introduces Craig to Kirstie, her sister, who is new in town. Kirstie designs her own line of jewelry, so Craig discusses the possibility of using her creations in a Siren fashion layout. Lilith walks into the club, catching the attention of every man. She orders a beer, twists off the non-twist cap, and provocatively licks the foam as it fizzes from the neck of the bottle. Kirstie’s glass explodes in her hand. As Lilith dances with Ken, a clearly mesmerized Rita asks who invited her, but nobody seems to know. Lilith crawls seductively on the floor, driving Rod into such a sexual frenzy that he pushes Ken aside and dances with her. Rod takes Lilith to his apartment building, and as they kiss in the foyer, a crazed Ken pounds on the locked front door. Lilith and Rod disrobe, and Lilith becomes a bright light. Ken smashes through the glass door, cutting himself, and Rod steps into an elevator shaft, thinking the elevator is there. He is impaled at the bottom of the shaft. The next morning, Rita summons Craig to her office to tell him that Rod is dead, Ken is in the hospital, and she is a suspect in Joseph Crenshaw’s murder because she inherited the magazine. Craig’s assistant delivers photographs from the party. Looking at them, Craig notices something strange about Rod and Ken’s expressions as they gaze at Lilith. Kirstie arrives at the office with photographs of her silver jewelry imbedded with birthstones. When Craig confides that his birthday is in February, Kirstie informs him his stone is amethyst, which ancient Greeks believed protected the owner from intoxication. Later, as Craig leaves the office, Lilith arrives to discuss her Siren photo shoot with Rita. When Craig visits the hospital, Ken reveals that Lilith was with Rod when he died, but goes into convulsions before he can say more. Later, Craig picks up Kirstie at Rita’s house. Kirstie is concerned about the intoxicating effect Lilith has on her sister. She spends the night at Craig’s apartment, making love. Meanwhile, Lilith seduces Rita and promises to give her great power. The next morning, Sadie, the black woman, stops Craig outside the Siren office and warns him not to turn his back on salvation. Craig is surprised to find that Rita and the photographers are shooting a new magazine cover with Lilith dressed in black, with lizard-like designs on her face. Craig warns Rita that the last-minute cover change will affect their deadline, but Rita ignores his concern. When Kirstie arrives with a piece of silver jewelry for the photographs, Lilith tosses it away. Craig objects, insisting that Lilith has no say in what she wears, but Rita angrily takes Lilith’s side. A large floodlight topples, barely missing Craig and Kirstie. Outside, Sadie again stops Craig and claims she needs to save his soul, but he pushes her away. He and Kirstie return to his apartment, and as they make love, Craig finds himself face to face with Lilith. As black snake-like things emerge from her mouth and bite him, Craig jerks awake, shouting in Kirstie’s face. He tells her he keeps having nightmares. Kirstie gives Craig a handmade silver amulet with an embedded amethyst, and asks him to let it hang over his heart. Later, in the photography lab, staffers become mesmerized by Lilith’s photographs and stroke each other. Craig snatches the photographs away, and as he glances at one of them, Lilith’s image beckons from behind flames. A telephone call breaks the spell. Kirstie informs Craig that Rita ordered her out of the house. Craig asks her to meet him at the nightclub. On the way, he notices a taxicab following him. At the club, Craig enters the bathroom and is confronted by a dwarf, who sends him into a room of freaks. Craig is welcomed, the dwarf announces, because he is “with Lilith.” Craig stumbles through a house of horrors, guided by a figure that looks like Kirstie until she turns into Lilith. The temptress takes control, but as she rips Craig’s shirt, the amethyst blocks her power and allows him to see her as a demon. Kirstie arrives at the club and is joined by Sadie, who warns her that Craig is in danger. Craig joins them and passes out. When he awakens, Sadie fixes a voodoo concoction and orders him to drink it. She explains that Lilith is "Satan’s whore" and Adam’s first wife who tempts men to their deaths. The amethyst hanging from Craig’s neck allowed him to escape, but tonight Lilith will be at the peak of her powers and hungering to take his soul. Sadie drives Craig and Kirstie to the Siren office in her taxi, and as they get out, Sadie orders Kirstie to stay close to Craig because her love is the only thing that can save him. In the office, the staff is in the throes of lust, and Rita is dead. Craig and Kirstie escape as the others try to grab them, but Ken hits Craig in the head with a baseball bat and grabs Kirstie. Sadie rescues the delirious Craig and drives him away. Sadie explains that she has followed the demon Lilith for years, because she killed her son, and warns that Lilith’s image on the cover of Siren will spread her evil nationally. They return to the magazine office to find Kirstie, but Ken has chased her into a wooded park. As Craig calls Kirstie’s name, Ken grabs her. Suddenly Lilith appears, draws Ken away from Kirstie, and rips out his heart. Sadie cannot run, so she gives Craig her special knife and instructs him to pierce Lilith’s heart. Seeing Lilith, Craig rushes to stab her, but the demon grabs his arm and entrances him. He drops the knife, and at her urging removes the amethyst talisman. As Lilith reaches a finger into Craig’s chest, Kirstie arrives and Craig announces that he loves her. The spurned Lilith returns to her original demonic form, and Sadie drives the knife into its heart. As flames consume Lilith. Craig and Kirstie embrace and Sadie praises God. Later, lying in bed with Kirstie, Craig picks up a copy of the new Siren. Blood oozes from Lilith’s image and a hand grabs his throat. He awakens.