Nonnatus House and the surrounding area is evacuated when an unexploded bomb is found nearby. Meanwhile, Shelagh has doubts about her wedding to Patrick, and Jenny and Trixie help a man who is suffering from shell shock.

Jenny is promoted to Acting Sister at the clinic, much to the chagrin of the more experienced Trixie. Meanwhile, Cynthia is taken in by the theories of a visiting doctor, and a troubled, desperate woman seeks help.

Sister Julienne and Trixie attend to the female inmates at Holloway Prison, where they meet a troubled young woman. Meanwhile, Jenny deals with a vain patient, Shelagh receives horrendous news, and the girls celebrate Chummy's birthday.

Sister Winifred treats a young Jewish woman whose mother is plagued by remembrances of the Holocaust. Meanwhile, Shelagh tries to find a new way to channel her energy, and Alec suffers a terrible accident.

Jenny returns and is seconded to the London Hospital, where she meets a fretting mother-to-be. Meanwhile, Chummy's mother visits, a patient of Cynthia's becomes mentally ill, and Tom's nervousness leads to trouble with Trixie.

Chummy struggles to cope with her mother's terminal illness, with her experience affecting Sister Monica Joan greatly. Meanwhile, Shelagh and Patrick receive encouraging news, and Jenny makes an important decision.