Terry Lambert (Steve Guttenberg) is sleeping with Sylvia (Isabelle Huppert), the wife of his boss (Paul Shenar). One night, while in Terry's apartment, Sylvia witnesses a man assault a young woman, Denise (Elizabeth McGovern), on the road below. Not wanting to reveal her affair with Terry, she keeps quiet. Terry instead steps forward, trying to help nab the criminal. However, he never saw the suspect and, when his lies are uncovered, the police begin to suspect his motives.