The film opens at a fashion show, where Chloe Keene struts the catwalk. She returns home to her boyfriend, Toby, and recounts a glamorous time in New York. After a tense phone call that goes nowhere, she tells a friend she will change her number. Later, at a shoot, she runs into her other boyfriend, Ned, who invites her to a reunion of his former band. She heads home and fibs that she will visit someone in Brighton.
Chloe drifts into sleep in the car, numbed by pills, and wakes upon arrival at the reunion. A stalker’s voice punctuates the quiet, different from the earlier call. At the gathering, she meets Stan, his wife Rachel, their deaf daughter Theresa, and Stan’s brother Gordon, who films the party. Over lunch, Ned’s wife Eve arrives and she is openly rude to Chloe, culminating in Eve cutting her hand on a glass. Eve’s chilling line—she wants Chloe to bleed to death—hangs over the table and unsettles everyone.
Outside, Chloe’s night takes a darker turn. Later, Stan finds her and says the others have left, offering her the chance to stay the night. While she’s in the bath, Rachel enters and asks what she thinks about the photoshoots; Chloe admits she merely pretends through them. When she returns to the bedroom, she discovers the handcuffs Ned gave her on the bed. A suspicious noise prompts a search, and Stan drags her back to bed after drugging her; she drifts back into sleep.
The next morning, Chloe wakes to the sight of Gordon watching the earlier tapes. He goes to bed, but Chloe swipes one and watches herself being coerced and assaulted. An attempted door opening sends her toward a window for escape, only to faint outside when she recognizes Stan waiting in the car. She regains consciousness in a basement, chained to the bed. Meanwhile, her persistent stalker Clive continues to phone, tapping away at the nerve of the situation. Theresa discovers the tapes and creates a poster to hand to the police, yet the officers dismiss it. Rachel hunts for the phone and the group decides to hide it in a shed.
Clive makes his way toward the house, but Rachel manages to dispose of him. He phones Chloe again and hears the shed’s ringing, prompting him to alert the police. Inside, Theresa locates Chloe but cannot free her cuffs. Ned arrives, insisting they must film a clip of Chloe “enjoying herself” if they’re ever to explain their absence to the law and avoid being charged as accessories to murder.
Stan orders Gordon to silence Chloe, and the trio prepares to drive her away. Clive, still in pursuit, is spotted by Ned and Rachel; a tense standoff unfolds as Clive tries to intervene, but the police arrive and arrest Stan. Back at home, Clive sits down to dinner and quietly watches Chloe return, calling her partner Toby. When she hangs up, the final twist lands: Toby reveals himself to be her other stalker, the second shadow watching Chloe all along.
