It's April 1970 and Trixie oversees the care of Arlene, an unmarried mother who is heavily pregnant and under the care of the district midwives. Rising rates of gonorrhoea in the district cause alarm when Zeta, a young Cypriot expectant mother, is diagnosed. She is utterly distressed and bewildered by her diagnosis and her husband Mehmet denies any extramarital affair. Meanwhile, Cyril and Rosalind volunteer together at the homeless shelter.

It's May 1970, and the Nonnatus team prepare for the arrival of a new nun and trainee midwife, Sister Catherine. Under Nurse Crane's supervision, Sister Catherine is thrown into a complex case. Dr Turner is taken aback when mother of seven Peggy Wrigley asks for an abortion. Although legal, the process isn't straightforward, and Dr Turner wants to ensure Peggy has thought this through. Meanwhile, Peggy's daughter Gail is expecting her first baby with a young RAF airman who is posted in Cyprus. Elsewhere, Dr Turner is disappointed by the general apathy towards the measles vaccination clinic as uptake remains relatively low despite the current high rate of cases.