Ángela, a university student in Madrid, is planning to write a thesis on audiovisual violence and the family. As she is sitting on a commuter train, it halts and passengers are told to evacuate. A man has committed suicide by jumping in front of the train. While being led out of the station, Ángela moves toward the tracks to see the man's remains. She is warded away at the last instant. At a thesis meeting, she asks her thesis director, Professor Figueroa, to help her find the most violent videos in the school's video library. After class, Ángela seeks out the help of a fellow student, Chema, who is known for his collection of violent and Pornographic film. While Ángela watches a violent film with Chema, Figueroa finds a tape hidden in the school's audiovisual archives. The next day, Ángela finds Figueroa dead of an apparent asthma attack in the university's viewing room. She takes the video tape from the player and leaves for class. A younger professor, Castro, takes over Figueroa's classes and the supervision of Ángela's thesis project. She goes to Chema's house to watch the film she stole. It is a snuff film, a film of a person being murdered. As they watch a woman being tortured, killed, and disemboweled, Chema realizes that she was Vanessa, a girl who attended their university and went missing two years ago. Chema is able to determine that the killer used a Sony XT-500 camera, based on the fact that it had a digital zoom feature, and that the film was shot in someone's garage.