While returning to Madrid after an illicit tryst, a wealthy socialite housewife and a university professor accidentally strike a bicyclist with their car. Although they see that he is still alive after the accident, they know they cannot summon help for him without their affair being revealed. They drive away and leave him to die. After the bicyclist's death is reported in the newspaper, the pair deal with ever-rising tension, borne from their fear that their deeds will be exposed.