A newborn infant is found dead in a wastebasket in the room of Sister Agnes, a young cloistered nun in a convent outside Montreal. She claims to have no memory of the conception or the birth of the child. Dr Martha Livingston is a psychiatrist who is appointed by the court to determine whether Sister Agnes is fit to stand trial for the murder of the baby. At the convent, this lapsed Catholic, who is very confident of her clinical skills, meets Mother Miriam Ruth, a worldly wise religious woman who wants to protect the fragile Sister Agnes from any further psychological pain. She believes that the young nun is 'touched by God'. After winning the trust of Sister Agnes, Dr Livingston learns about her sheltered life and her obsession with God and suffering. All attempts to find out who is the father of the baby are fruitless. Throughout the investigation, Dr Livingston and the Mother Superior are adversaries; only when they share cigarettes and speculate on what the saints would have smoked do they tear down the wall of distrust that divides them and recognise their mutual concern for Agnes.