A woman thinks her plot to murder her husband is foolproof - but it will set off ricocheting complications. When a stranger calls at an old inn during a vicious storm, the elderly resident and her manservant concoct a sinister plan. A travelling salesman picks up a secretly dangerous hitch-hiker. A woman telephones a private detective agency and hangs up abruptly, piquing the curiosity of the investigator. And a knife thrower's assistant is murdered - but is her jealous partner responsible?