Thelma Jordon shows up late one night in the office of Assistant District attorney Cleve Marshall, a married man, who would rather get drunk than go home. She tells him a story about prowlers and burglars. He asks her to join him for a drink and she agrees. Before Cleve can stop himself, he and Thelma are involved in a love affair. But Thelma is a mysterious woman, and Cleve can't help wondering if she is hiding something.