Billy Hughes, a mute special-effects makeup artist, is in Moscow working on a low-budget slasher film directed by Andy Clarke, the boyfriend of her elder sister, Karen Hughes. One night, Billy returns to the set to fetch a piece of equipment for the next day’s shoot and finds the studio locked behind her. She phones Karen for help and communicates via Morse code, but she discovers an after-hours crew shooting a cheap pornographic film. Watching unseen, Billy is amused until the performance turns sadistic. When Arkadi, the masked actor, pulls out a knife and brutally stabs the actress to death, Billy reacts and is discovered. She flees through the studio, pursued by the film’s director, Lyosha, before crashing through a window outside. Moments later, Karen Hughes arrives and finds the injured Billy, with Lyosha standing over her. Lyosha pretends to be an innocent bystander who witnessed Billy’s accident, but Karen senses he is dangerous based on Billy’s body language.
Police arrive and question Lyosha, but come to the conclusion that Billy witnessed an elaborate special-effects sequence being shot, since they cannot find a body. Arkadi, the man Billy witnessed stab the actress, later demonstrates the effects using a fake knife that streams blood, frightening Andy Clarke when he pretends to attack him with it. Billy insists the prop knife is hers, and that Arkadi stole it. Billy leads police to an elevator shaft where she believes Lyosha stashed the actress’s corpse, but they find it empty. After police dismiss the incident and send Billy home, a night watchman at the studio finds the actress’s corpse burning in a basement incinerator before being stabbed to death by Arkadi.
Shortly after, a mysterious elderly man arrives at the studio in a vintage car and asks Lyosha if things “went smoothly.” Aware that Billy witnessed the murder, The Reaper makes clear that she must be eliminated.
Meanwhile, a detective, Larsen, begins looking into Billy’s claim, believing there is truth to it, as rumors swirl about an international crime ring making and selling snuff films in Moscow. The operation is led by a wealthy financier known as “the Reaper.” Back at Billy’s apartment, Billy communicates with Karen using a digital dictation machine. In the midst of their conversation, Billy’s doorbell rings, and she is confronted by Arkadi, who breaks in, followed by Lyosha. A violent struggle ensues, during which Billy manages to electrocute Arkadi in the bathtub with a hairdryer. Lyosha incapacitates Billy, but Larsen beats Lyosha unconscious and saves her.
Larsen quickly escorts Billy away and explains that the crime ring has targeted her, believing she is in possession of a computer disc containing confidential information. Meanwhile, Karen and Andy arrive at Billy’s apartment and find it disheveled, then are attacked by Lyosha who awakens. Two of the Reaper’s thugs posing as policemen arrive at the scene, shoot and kill Lyosha, and question Karen and Andy about the disc. Meanwhile, Billy directs Larsen to the film studio, believing the computer disc is located there.
Karen and Andy hurry to the studio, where Andy tries to shoot Larsen as he arrives with Billy, mistakenly thinking Larsen means her harm. In the ensuing chaos, Billy rushes outside and is confronted by the Reaper’s armed men. Larsen shoots Billy multiple times, making it appear that she is killed, and hands over the sought-after disc to the Reaper. The Reaper and his gang depart, and Karen begins to beat Larsen in anger. However, she quickly realizes that Billy is still alive, as she opens her eyes and reveals remote-controlled squib blood packs hidden under her clothes; Larsen had orchestrated the fake murder to spare Billy’s life. The only thing Larsen does not understand is why the Reaper didn’t take the disk.
Larsen plans a follow-up meeting with Billy the next day, and brings along one of the studio’s corrupt security guards, whom he has bound and gagged. As they are about to drive away, Billy realizes the guard is worried—the car has been rigged with a bomb and the reason the Reaper did not take the disk is that it will be destroyed when the car explodes. With help from Andy, she communicates this, and Larsen escapes the vehicle seconds before the explosion.
