As told to a psychiatrist Mr. Peabody, middle-aged Bostonian on vacation with his wife in the Caribbean, hears mysterious, wordless singing on an uninhabited rock in the bay. Fishing in the vicinity, he catches...a mermaid. He takes her home and, though she has no spoken language, falls in love with her. Of course, his wife won't believe that thing in the bathtub is anything but a large fish. Predictable complications follow in rather tame fashion.

A man (Young) comes round after a car accident, and realises that a perfect crime is now possible any movie with this scene can't fail. From this halfway point, the anxious mood of this rare noir thriller thickens fast. Jane Greer and Susan Hayward in turn tempt Young (a spineless louse) from his rich wife (Johnson). We know he's wretched, but is he guilty of murder