Motel operator Ann Porter and bar owner Dan Mullins decide to set up a key club to satisfy sexually their clientele. The club's membership consists largely of married people seeking extramarital sexual excitement. Inhibitions are cast aside and some unexpected results are achieved: Bob and Patti, a married couple who have independently joined the club, by chance receive matching room keys; and their encounter revitalizes their their faltering marriage. Meanwhile, some of the married women discover that they are sexually attracted to other women. Ann and Donn eventually throw a party for their clients. The members indulge their individual sexual preferences and all goes well until the husband of a participant, Sharon, makes an unexpected appearance and begins to beat her. Bob tries to intervene and he is accidentally killed by the jealous husband. The police then raid the party and break up the key club.