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.
Karlheinz Böhm
as Mark Lewis
Anna Massey
as Helen Stephens
Moira Shearer
as Vivian
Maxine Audley
as Mrs. Stephens
Brenda Bruce
as Dora
Miles Malleson
as Elderly Gentleman Customer
Esmond Knight
as Arthur Baden
Michael Goodliffe
as Don Jarvis
Jack Watson
as Chief Insp. Gregg
Shirley Anne Field
as Pauline Shields
Pamela Green
as Milly
John Barrard
as Small Man (uncredited)
