Ángela (Torrent) is a film student at the Madrid's University Complutense. Searching for research material for her Thesis (hence the film's title) on audio-visual violence, she attains the friendship of Chema (Martínez), a fellow student and introvert with an encyclopedic collection of violent and pornographic films.After her professor dies while watching a film she steals the videotape, discovering that it is a snuff film featuring a girl whom she and Chema recognize as another student at the university - and a former girlfriend of current student Bosco (Noriega). Investigating the origins of the tape, they are drawn into the operations of a chilling snuff ring.