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.

Now dating surveyor Alec, Jenny joins the other midwives in their superior new base, along with latest recruit, Sister Winifred. Jenny is concerned for Merle and Billy, a young couple whose infant boys are permanently ill, causing them to doubt their parenting skills, whilst added is stress provided by the fact that Billy's brother died as a toddler. Surprisingly, Sister Monica Joan accidentally provides Dr. Turner with the solution to the children's complaints, thus saving them. Chummy, meanwhile, drums up support for the newly opened, but under-used ante-natal clinic, taking advantage of a royal visit to put it in the spotlight. The day is a success, and to add to it, Chummy helps an older woman with a difficult birth, resulting in Sister Julienne asking her to return to work.

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.

As Jenny takes compassionate leave after Alec's death and Sister Julienne collapses with exhaustion Shelagh returns to help out and efficient nurse Patsy Mount arrives. They start to plan for a party to mark the jubilee of Sister Evangelina taking holy orders but are interrupted by irate Mrs Harper, whose daughter Sally, a young woman with Downs Syndrome, is pregnant. The father, cerebral palsy sufferer Jacob, lives in the same residential home and they declare that they are in love and aim to marry but the baby is stillborn and Jacob is sent to another home. News of Evangelina's celebration attracts her brother Vincent, now an alcoholic tramp, and she steals food for him and sees him admitted to hospital, but her party goes ahead - despite her protests - and the community shows their appreciation of her work over the years.

Patsy's brusque manner sees her taken off midwifery duties and reassigned to district nursing, where a patient reminds her of her past. Meanwhile, Trixie deals with a couple whose relationship has separated them from their families.

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.