Christmas promises to be a memorable one at Nonnatus House as Lucille and Cyril prepare for their upcoming winter wedding. Meanwhile, the team face their busiest Christmas yet.

Sister Julienne and Dr. Turner clash over whether to provide a private care service, and a distressing birth raises fears of another Thalidomide case.

Sister Frances finds herself in a tricky situation when a pregnant woman confides in her. Sister Julienne's new venture hits a stumbling block.

Sister Hilda and Dr. Turner are involved with a young woman whose health presents a series of challenges. A complicated pregnancy leads the Nonnatus team on a path of discovery.

It's July 1966, and Britain is in the grip of World Cup fever. New pupil midwife Nancy makes quite an impact.

With sister Hilda away on a refresher course, sister Julienne steps in to carry out home visits. The new pupil midwives are settling in well, and there is a sense of hope in the air. 

While examining expectant mother Vera Sands during a routine visit, sister Julienne is concerned by her toddler daughter who is displaying troubling symptoms. Determined to find out what's wrong, sister Julienne and doctor Turner are on the case. 

Meanwhile, an overly protective mother struggles to cope with her daughter's teenage pregnancy and is insistent on keeping it low key, much to the frustration of new pupil midwife Nancy Corrigan. 

It's September 1966, and at clinic Trixie is tasked with examining a desperate woman who is pregnant with her fifth child. Trixie learns that her patient's personal life is far from stable, compelling her to speak out publicly. However, the results garner mixed reactions from Nonnatus House and the community.

Dr Turner and Sister Frances are entrusted to help a mother-to-be who refuses medical care through her final weeks of pregnancy, and Nancy Corrigan reveals a secret about her background that could threaten her relationship with Sister Julienne and Nonnatus House.

Nonnatus House struggles to come to terms with Nancy's revelation. With Sister Julienne taking her annual leave at the Mother House, Sister Hilda relishes the chance to cover and impress with her leadership.

While attending an expectant mother, Sister Frances and Trixie are appalled to learn that Poplar's housing crisis is worsening, leaving the Nonnatus team vowing to fight for change.

It's a poignant time for the Turner family as Timothy readies to leave for medical school in Edinburgh and Cyril receives news from home, prompting him and Lucille to consider their own future.

Meanwhile, a very special baby is born, who causes a rift in a close-knit family and leads many people to count their blessings.