A woman once convicted of euthanasia gets a job caring for her prosecutor's wife.

After spending 2 years in prison for the mercy killing of her incurably ill lover, Canadian Dr. Christine Allison accepts employment with Stephen Dane, the prosecuting attorney at her trial. Dane explains that he wants her to look after his wife, Liane, who has been mentally unbalanced since she caused the death of her father in an automobile crash. Gradually, however, Christine begins to suspect that Dane has another reason for hiring her and is not really concerned about his wife's welfare. Her doubts increase when Liane's supposedly dead father, Captain Ferris, reappears. Determined now to help Liane, Christine takes her to her alleged lush country home in Ireland. The shock of having to admit that it is a hovel and that her father is a drunken schemer is too much for Liane, and she suffers a breakdown. On a doctor's advice, Christine gives her a sedative. When she finds Liane dead from an overdose, Christine fears that Dane arranged matters so that again she will be charged with mercy killing. But he defends her and traps Captain Ferris into admitting that he hid the empty bottle after Liane took all the pills it contained. After confessing complicity in the death of his daughter, Captain Ferris falls to his death.