Based on the screenplay by Mel Dinelli, this story revolves around Helen Warren, a beautiful mute girl, who becomes the target of a mysterious killer who preys on young handicapped women.

Pursued by detectives, Johnny Walters leaves the city to visit his family in a small California town. Among the household: his dead brother's luscious widow Helen, who soon is attracted to him. Ominous events and conflicting evidence leave Helen suspicious, but uncertain about her brother-in-law as tension builds...

Wealthy writer Stephen Byrne tries to seduce the family maid, but when she resists, he kills her. Long jealous of his brother John, Stephen does his best to pin the blame for the murder on his sibling. Also affected by Stephen's arrogant dementia is his long-suffering wife Marjorie.