A pattern is developing murder committed by a man who stops cars being driven by prosperous businessmen and Roger ( Handsome ) West of Scotland Yard must solve the case. Muriel Arlen waits for husband Wilfred, but when the key turns in the door it is a masked stranger that enters the house and knocks her out with the butt of a gun. West has problems in getting to the truth as people he is trying to protect lie, and his assistant falls in love with a witness. Meanwhile, the murderer is at large "