London is terrorised by a serial killer who strangles women with his tie. When two of the victims are found to be the ex-wife and girlfriend of the same man, the police incorrectly suspect him of the crime. Aided by his friends, he goes on the run from the law in an attempt to prove his innocence. Alfred Hitchcock's thriller, starring Jon Finch and Barry Foster.

London is terrorized by a vicious sex killer known as The Necktie Murderer. Following the brutal slaying of his ex-wife, down-on-his-luck Richard Blaney is suspected by the police of being the killer. He goes on the run, determined to prove his innocence.