Sally Fulton is a hospital almoner, who left the job, for which she had a genuine vocation and aptitude, to marry a radiologist, Tony. The marriage was a failure and she has never understood that the chief cause of this was her deadly inclination, all too common among professional women, to bring her professional technique into her private life and to its problems. Tony leaves her, and she subsequently divorces him. Returning to her former job, though in another hospital, she is haunted by guilt, for the only fault she has been able to recognise in her own past conduct is her former jealousy of a girl lab assistant who had attracted Tony's attention. Unexpectedly Tony is brought to the hospital as a surgical emergency, dangerously ill. Sally now begins to learn how desperately wrong she was about him, and about herself. After their divorce he had not married the little 'lab' girl, but someone quite different. Sally's guilt is increased, and she is further confused by the fact that she now loves and is loved by one of the surgical registrars at the hospital.
In an overwhelming impulse to atone in some way for the past before beginning a new life, she gets into touch with the 'lab' girl, Hazel, finds her in very poor circumstances, and gets her a job at the hospital. But Hazel is a born delinquent, a type quite beyond Sally's experience and comprehension. As Hazel sinks further and further Sally goes on trying frantically to save her. Her obsessive conscience and her trained zeal in following up this 'case', very nearly wreck her engagement. Sally crashes blindly along the path of Hazel's redemption, only to find that it leads straight into a pit of despair and death. From that pit she herself emerges, freed of her obsession, to find happiness but at a terrible cost, for two people die as a result of her innocent, essentially well-meaning interference.