When a baby is born with severe deformities of the kind later identified as caused by the drug thalidomide, the midwives find it difficult to handle the situation, and the baby's father rejects her completely, to his wife's dismay. Trixie's new sideline as a keep fit instructor brings her into conflict with Sister Julienne, and she also becomes suspicious of the relationship between Barbara and Tom. Rather than return to Wales as her mother wishes, Delia moves into Nonnatus House.

Barbara treats a pregnant woman whose dockworker husband is struggling to support her as opportunities for work dry up. She is forced into a difficult decision that leaves Barbara facing the biggest test of her career. Nurse Crane meets a kindred spirit when she learns to speak Spanish, and Sister Evangelina helps a woman with breastfeeding, leading to unforeseen consequences.

Dr Turner helps the Mullucks cope with the stresses of caring for a disabled child as the terrible legacy of thalidomide becomes apparent and Nurse Crane faces an unexpected crisis.

An unexpected turn of events leads to a wedding being hastily arranged. Shelagh finally goes into labour. The arrival of the pill leads to unforeseen consequences.

The winter continues, and the team at Nonnatus House welcome their newest midwife, Lucille Anderson. Nurse Crane and Dr Turner care for an elderly cancer patient facing eviction.

Dr Turner gets involved with a troubled young man, and Lucille makes new friends. Meanwhile, Barbara lies ill in hospital.

The team must rally to prepare for Sister Monica Joan's birthday. Meanwhile, the closing of a nearby maternity home brings an influx of expectant mothers to the Nonnatus midwives.

Nonnatus House welcomes two new nuns. Valerie deals with a shocking case that arrives unexpectedly, and the other midwives must handle a complicated multiple birth.

Trixie helps a blind mother, Marion, care for her new baby, but trouble starts when Marion’s sister calls Social Services to intervene.

Sister Julienne decides it is time to take matters in hand when a letter arrives from the council saying that it will cut funding to Nonnatus House and no longer pay for the accommodation, and goes to see Violet at one of her open sessions as a local councillor.

Nonnatus House suffers its biggest threat yet. But this time it’s not the bricks and mortar that are in danger, it’s the people.

April 1968. Racial tensions cast a shadow over Poplar, Nancy’s eyes are opened when she supports a dying woman, and Nonnatus House welcomes a new sister.

Sister Julienne helps care for a first-time mother who is going through a challenging diagnosis. Lucille struggles with her own health, and Poplar celebrates the Whitsun Maypole.

As Poplar prepares for Christmas, Sister Monica Joan fears this could be her last. Dr Turner and the midwives deal with a complicated multiple birth, and Cyril helps a war veteran.