Webb Garwood (Van Heflin) is a cynical policeman who believes that success comes from lucky breaks. Responding to a prowler complaint at the home of Susan Gilvray (Evelyn Keyes), he is immediately attracted to her and her wealth.
He returns to check up on Susan, and they begin an affair, conducted while listening to her husband William (Emerson Treacy)'s all-night radio program. Feeling guilty, Susan ends the relationship, but Garwood remains obsessed. He pretends to be a prowler on the Gilvray property so he can respond to another police call.
Drawing William outside, he shoots him and makes it appear accidental. When Garwood manipulates Susan's confusion about the shooting, she buys his story, and the lovers marry. However, upon discovering that Susan is pregnant too soon, they flee to give birth in secret, but eventually Susan learns the devastating truth.
Intense performances by Heflin and Keyes bring alive this story of a prowler who preys on a woman's loneliness while also representing the forces of authority who literally screw those they are supposed to serve.