Money and power have brought Mrs Garth a charming husband. But despite her beauty and intelligence, she receives neither his loyalty nor his love; instead, he is infatuated with her young niece. Her domineering ways have also alienated her only secretary, Richard Corbett. In her safe she holds cheques once forged by Corbett and, while she is alive, he must remain within her service. To gain their freedom, the two men contemplate murdering Mrs Garth. One weekend their plans become reality with chilling consequences.