It's diabolical! It's daring! It stalks, it cuts, it rips!

At Heathrow Airport, a man is razored to death in a toilet cubicle. A young woman, Peggy Foster, is concerned about the disappearance of Michael, her photographer boyfriend, who has been in Vietnam for months. In order to pay the rent, she reluctantly sub-lets her garret flat to a man called John Kirk Lawford. The new tenant wears sunglasses indoors and acts suspiciously. Peggy is lured to an abandoned airfield by a call from Michael but is shot at by a sniper. Back at her apartment block she is shocked to find that a man has apparently committed suicide by jumping from her balcony. While the police question Peggy, a stranger turns up and announces himself as John Kirk Lawford! Shirley, secretary to Peggy's lascivious publisher, is killed by a black-gloved intruder and the mystery deepens...