Jake wakes up bound and bloodied, with chains around his arms and neck as a VHS camera rolls. The host, Barry Miller, greets him like a winner and explains there are three boxes, each containing a prize. Jake chooses the middle box, which holds a shotgun, and the host shoots him, ending the room’s grim game in a swift, brutal moment.
Four friends—[Anita], [James], [Matthew], and [Melissa]—arrive at James’s uncle’s cabin for a weekend that promises laughs and escape. That night, they discover a video camera set up in the yard. Some want to watch the tapes, others are wary. While intoxicated, Anita blurts out that they’re only friends with James because his parents are rich, a remark that enrages James and hits close to home given Anita’s dying mother. When [Matthew] tries to comfort Anita in her bed, he cannot wake her. He quickly realizes [Melissa] is unresponsive too, and as he attempts to flee, he’s stabbed by a needle that knocks him out.
They awaken in an underground facility, restrained by metal collars around their necks. The host, an eccentric, mask-covered man, unmasks himself and reveals the truth: he is the show’s host, orchestrating a series of sadistic games before a fake audience of mannequins. The captives are forced into torturous rounds—rock, paper, scissors—with brutal results: Matthew is bludgeoned, James’s finger is severed, and Melissa’s mouth is cut open. During another round, the group is compelled to reveal their worst deeds. Matthew admits scamming an elderly couple, Melissa sold violent pit bulls to a dog-fighting ring, James let his father take the blame for a fatal crash, and Anita admits she sold pornographic content of herself to pay for her mother’s surgery.
Melissa loses the next game, and the hydraulic press crushes her head. After removing the body, the host drops his mask and directly confronts Anita, who cowers in fear and apologizes. A flashback reveals Barry Miller’s darker past: he was a successful TV host who employed Anita. During a lunch break, Anita’s colleagues Jake and Rebecca discuss the money to be made from falsely accusing sexual assault after another talk-show host, Collin Piper, is found innocent. Barry surprises Anita’s circle with a birthday cake, congratulating her on her hard work, while Rebecca speaks out against the inappropriate attention. Jake and Rebecca convince Anita to accuse Barry, leading to Barry’s firing and his wife leaving him.
Back in the present, James pleads with Barry to let them go, offering that James’s father can help restore Barry’s life. Barry shows Anita the severed head of her lawyer, the legal aide who helped convict him, and, when Anita refuses, James tries to strike Barry. Barry responds with an electric shock that knocks the group unconscious.
When they regain consciousness, James and Matthew are strapped to tables. A grim twist reveals two keys sewn into their stomachs—one key in James and one in Matthew—that can open a door to escape. James promises to hand over all the money to Anita and her mother if she chooses Matthew, but she nonetheless goes after the key in James. The key in James’s stomach does not unlock the door; the true key lies with Matthew. Barry frees Matthew to fight James, and Matthew confesses his love for Anita before slitting his own throat.
Anita awakens again to find the bodies removed and the makeshift dressing room door open. Barry’s room holds photos and VHS tapes of his previous victims, a grim gallery of his past. Barry forces Anita to sit before three presents, echoing the game from the opening credits with Jake. In a tense, intimate moment, Anita and Barry seem to reach a fragile understanding, but the danger remains. Barry promises that if she plays the final game, he won’t target her mother. She selects the center string, revealing a birthday cake. Barry begins to sing “Happy Birthday,” and Anita makes a move to escape, attacking him and fleeing outside. He electrocutes her to pull her back inside and continues the brutal “celebration,” slamming her face into the cake. The chemical burn finally melts her features, killing her.
The final scene returns to a VHS tape: Barry forces the talk show host, Collin Piper, to admit his crimes before brutally murdering him in the name of justice.
