Shell Game — Richard Powell

Bill Stuart is vacationing in Florida, collecting shells, when one evening he stumbles upon a beautiful young woman hiding under a fishing pier on a deserted beach. Undaunted by her cock-eyed story, he offers her a lift into town. Valerie agrees if she can drive. When she discovers they are being followed by a gray sedan, Valerie breaks every law to shake them; and just as mysteriously does a quick disappearing act when they arrive at the bus station. The local chief of police isn't interested in tracking his missing person, so Bill heads back to the beach to retrace Valerie's footsteps -- which just happed to lead to a cabin that is occupied by the body of a very recently murdered man!