Bank employee William Marble (Charles Laughton) risks losing his job if he can't pay off his massive debts. When William's wealthy nephew, James, visits, William repeatedly attempts to borrow money. After James turns him down every time, William poisons him. He then invests James' money and becomes rich enough to retire, but the guilt of his actions weighs on him. Sending his wife (Maureen O'Sullivan) and daughter away on vacation does not help, as he begins an affair that further traps him.