Christmas 1966 promises to be a memorable one as Lucille and Cyril prepare for their upcoming winter wedding.

Christmas 1966 promises to be a memorable one as Lucille and Cyril prepare for their upcoming winter wedding.

It's April 1968 and change is coming to Nonnatus House. Racial tensions cast a shadow over Poplar, and the sisters welcome a new recruit.

Sister Veronica is shaken when a mother reveals a terrible truth about her marriage. Shelagh cares for a baby with a life-threatening condition, and Nancy harbours a secret.

The maternity home is thrown into chaos by an outbreak of gastroenteritis, and Nurse Crane fights to save her career. Meanwhile, Cyril encourages Reggie to seek help.

A pregnant mother with a chronic heart condition falls unwell. Nancy grows suspicious of a young father's erratic behaviour, and Matthew prepares for a visit from his father.

Trixie supports an underage mother through a difficult time, Monica Joan welcomes an unusual guest to Nonnatus House, and Sister Veronica spearheads a new council initiative.

Nancy makes a home visit to Imelda O'Connor, and is surprised that Imelda, her husband Maurice and young son Paul are living in a cramped caravan on a building site.

Dr Turner experiences the biggest test of his career, while Trixie's approaching nuptials cause stress levels to escalate. Sister Julienne hatches a plan to save Nonnatus House.