8MM

Private investigator Tom Welles is approached by Daniel Longdale, the attorney representing wealthy widow Mrs. Christian. She seeks answers about an 8mm film discovered in her late husband's safe, which seemingly depicts a real murder.

Upon examining missing persons files, Tom identifies the victim in the film as Mary Ann Mathews. Determined to uncover the truth, Tom visits Mary Ann's mother, Janet, to discuss her daughter's fate.

While searching Mary Ann's home with her mother's permission, Tom discovers the young woman's diary. The diary reveals Mary Ann's aspirations of becoming a film star in Hollywood and includes a note addressed to her mother.

Tom travels to Hollywood to delve into the world of illegal pornography, assisted by Max California, an employee at an adult video store. Together, they navigate the dark and dangerous underbelly of the film industry.

Tom's investigation leads him to a sleazy talent scout, Eddie Poole, and eventually to director Dino Velvet. Velvet, known for his violent films, seems to have connections to the mysterious 'Machine', a central figure in the case.

Tom pretends to be a client interested in a dark film project, arranging a meeting with Velvet in New York City. The situation turns deadly when attorney Longdale reveals the film in question is a genuine snuff film.

During the meeting, Max is captured and tortured by Velvet and Machine, who intend to use him as leverage against Tom. The situation escalates as violence erupts, leading to Max's tragic demise.

Realizing the extent of the criminal operation, Tom threatens Velvet and Poole with the truth about Mrs. Christian's payment for the film. The confrontation becomes increasingly violent, resulting in the deaths of both Velvet and Longdale.

Tom informs Mrs. Christian about the horrifying truths he has uncovered and advises her to contact the police. Upon arrival at her estate, he learns that she has tragically taken her own life after receiving the news.

Determined to avenge Mary Ann, Tom tracks down Eddie Poole, confronting him at the location of the crime. Overcome with rage, he brutally beats Eddie to death and burns the evidence to sever ties with the past.

Tom locates Machine in his home and upon confronting him, unmasks him as the mild-mannered George. In a tense struggle, Tom learns about George's sadistic motivations, leading to a fatal confrontation.

After exacting his revenge, Tom returns to his family, burdened by the weight of his actions. He reflects on the emotional toll of his investigation and the lives lost along the way.

In the aftermath, Tom receives a letter from Mrs. Mathews expressing her gratitude for his efforts. She acknowledges their shared sorrow for Mary Ann, highlighting their connection through loss.