Quinn, a socially reserved college student and sorority member, attends a large Halloween party in Salem despite her usual preference for staying in and reading. After drinking the strong Halloween punch, she dances on the fog-filled dance floor. A stranger begins grinding against her and groping her, ignoring her repeated demands to stop. She finally breaks free, and the man retaliates by splashing beer in her face.
A tall figure in a Ghostface mask, the white-faced killer from the
Scream horror films, rushes in and beats the man unconscious, threatening to kill him if he ever touches Quinn again. Quinn feels an immediate attraction and mentally calls the stranger Ghost. A second figure wearing a Jason Voorhees hockey mask, another iconic horror villain, appears and restrains Ghost, revealing they are friends. Quinn impulsively leads Ghost upstairs to an empty room. Jason follows, and a third friend dressed as Michael Myers, yet another horror-film killer, arrives in response to a text. Ghost dismisses both men so he can be alone with Quinn.
Ghost tells Quinn he has been watching her all night and states bluntly what he wants. Quinn reciprocates but sets one condition: The encounter ends at sunrise. Ghost does not truly accept the limit, telling her she will always be his regardless. He blindfolds her with the belt of his costume and performs oral sex on her, bringing her to multiple orgasms. When he removes the blindfold, Quinn discovers Jason and Michael had entered and watched. She is shocked, but Ghost says he will share her only with her consent. Before she can respond, a group of guys dressed as football players bursts in, making vulgar threats. Jason pulls Quinn behind him and Ghost to shield her. Quinn defuses the confrontation by pulling Ghost from the room, but when one player threatens to find her later, Ghost charges back in, pins the man to the wall with a knife at his throat, and breaks his nose.
In the kitchen, Quinn encounters Veronica, the girl who tormented her throughout middle school and high school. Memories flood back: Veronica and her friends bullied Quinn relentlessly on social media, so pervasively that Quinn could not have a cell phone or computer growing up. They cruelly told her that her father's death by suicide was her fault. Quinn's memories also include self-harm. With Ghost's arm around her and Jason and Michael flanking her, Quinn stands her ground. When Michael orders Veronica to hand over the last blue raspberry Jell-O shot, Quinn instead takes a cherry one, tells Veronica it was not good to see her, and walks away.
Quinn retreats to the bathroom, overwhelmed by a panic attack. Ghost follows, and she asks for a distraction. He responds by initiating an aggressive sexual encounter, during which Quinn experiences her first orgasm caused by a partner. After they return to the dance floor, another man grabs Quinn's wrist and refuses to let go. Ghost shoves the man into a wall and drives his knife through the man's palm. The crowd scatters, and the group immediately leaves the party. Quinn's feet blister from her heels, so Ghost carries her. At a house, he removes his mask for the first time, revealing blue eyes, black hair, neck tattoos, and sharp features. Quinn feels certain she has seen him before but cannot place him. He tells her he is not her hero but "the villain" who wants her for himself. He gives her a ten-second countdown to leave, warning that staying means committing to the rest of the night. Quinn refuses to go.
Inside the apartment, Ghost encourages Quinn to voice her fantasies. She admits she has only read about being with multiple partners, and Ghost and Jason both engage sexually with her. Afterward, Ghost notices healed scars on Quinn's wrists. He presses her, connecting her panic attack to Veronica, and Quinn opens up for the first time. She tells Ghost and Jason about the relentless bullying and about being told her father died by suicide because of her. Ghost becomes enraged. Jason asks if Quinn knows those claims were lies; she cannot fully say she does. She explains she never told anyone, not wanting to burden her mother. Ghost declares her bullies will pay with their lives. Quinn reveals they all work at the local Salem haunted house attraction and names the three worst offenders: Derek, John, and Alex.
The group rides motorcycles to a secluded lot near the haunted house. Ghost instructs Quinn to stay hidden in the woods. The narrative shifts to Ghost's perspective as he, Jason, and Michael enter the building. Ghost stations Michael at the front entrance and Jason at the exit. Once the last guests have left, Ghost hunts his targets. He stabs Derek to death after Derek mockingly dismisses Quinn and her father. He kills John next, declaring each wound is for every year Quinn was tortured. He finds Alex chained to a chair with duct tape over his mouth and slits his throat.
Jason douses the building with gasoline and sets it ablaze. Quinn appears at the back door, having disobeyed Ghost's orders out of concern for his safety. Ghost has sex with Quinn on the floor as flames consume the building around them. Smoke thickens and screams echo through the halls. Ghost carries Quinn outside as they choke on smoke, then frantically checks on her. She opens her eyes and reassures him she is safe.
As the four reach their motorcycles, police spot them and give chase. Ghost signals for Michael to take a side street with Quinn while he and Jason ride toward the officers as a distraction. At the apartment, Quinn paces in anguish, consumed with guilt over the fire. Michael removes his mask, revealing blond hair and brown eyes, and calms her panic attack with breathing exercises. Ghost and Jason burst through the door covered in blood. Quinn runs to them in relief, kissing all three men. The group shares a final sexual encounter before settling into a quiet, tender aftermath.
Quinn later joins Ghost in the shower, where the water runs red with blood. She asks what he did to her bullies, and he deflects, telling her he would sell his soul for her if he had one. Reminded of her condition, Quinn extracts herself from Ghost's sleeping embrace at sunrise and leaves. Jason catches her in the kitchen and challenges whether leaving is truly what she wants. Quinn insists it was one night, takes the coffee he offers, and walks out.
That afternoon, Quinn goes to the Salem public library but cannot concentrate on her book, her mind consumed by thoughts of Ghost. He appears across from her, visibly agitated. He tells her he has been "watching her from the distance for too long" (103). Quinn realizes she had seen him before, on campus, at the park, the mall, and around Salem, which explains why he looked familiar. Ghost declares that after having her, he is keeping her. He tells Quinn to say she is his. Without hesitation, she obeys, abandoning her sunrise deadline and accepting that she belongs to him.