The opening of the movie reveals a couple having breakfast, then going on a road trip or outing, when suddenly Amos (Kirk Douglas), who is driving, and his wife are involved in a major accident that claims her life and severely injures him. Amos wakes up in a hospital, to realize that his wife died as a result of the accident and his home has been sold.
Amos is sent to the Sunset Nursing Home. There, he meets an old baseball friend and gets in a relationship with a female resident, Hester. The head nurse, Daisy Daws (Elizabeth Montgomery), is notorious for running the facility with strict rules that are enforced by Roland, an orderly (male CNA). Daisy also has an affair with the local Sheriff so none of the residents dare to complain about her. Even when a County Commissioner, Burt, pays a surprise visit, he is only told good things about the facility and Daisy.
One night, Daisy administers an overdose of barbiturates to Amos' roommate, while Amos pretends to be sleeping. He watches it happen and can't do anything about it. Later, after the remains are picked up by morticians, Amos questions Daisy of why she did that and she threatens to do the same to him unless he puts his life insurance policy in her name.
Amos' grandson pays him a visit and offers to let his grandfather come live with him, but Amos does not want to abandon his friends in the nursing home.
Amos then sneaks into Daisy's bedroom to steal a syringe, needle, and the barbiturates which were used to euthanize her residents. He picks a fight with Roland so that he suffers bruises and other skin injuries, injects himself with the barbiturates and is found dead the next morning. Just before he administered his own lethal injection, Amos had written a letter to the state that Daisy forced him to put his life insurance on her name, he fears she will kill him, and if he dies, an autopsy should be performed and that the benefits from his life insurance policy should be shared between his grandson and Hester.
Faced with the letter that Amos wrote and the results of the autopsy (which reveals "enough barbiturates to kill seven people"), the Sheriff arrests Daisy despite her screams and threats to expose his infidelity.