Loner Mark Lewis works at a film studio during the day and, at night, takes racy photographs of women. Also he's making a documentary on fear, which involves recording the reactions of victims as he murders them. He befriends Helen, the daughter of the family living in the apartment below his, and he tells her vaguely about the movie he is making.

Peeping Tom is a chilling, methodical look at the psychology of a killer, and a classic work of voyeuristic cinema.