Jenny Lee start her midwife career at Nonnatus House in London. She is surprised to find that it is a nursing convent and not a hospital. Her first case is a woman pregnant for the 25th time!

A new girl arrives Nonnatus House and finds it hard to earn the respect of Sister Evangelina. Jenny sees an unfamiliar darker side of life following an encounter with a runaway.

A baby girl is snatched from her pram and the local community unites for the search. Cynthia sees another sort of loss as she tends to soon-to-be parents David and Margaret.

When Peggy’s brother is diagnosed with cancer, Jenny and the nuns are called upon to care for him. Jenny gets to know the siblings better. The Nonnatus House residents get involved in Fred’s latest money-making scheme which involves a pig called Evie.

When Chummy's imperious mother visits and disapproves of Peter Noakes, Chummy defies her mother and has her wedding on her own terms. Senile Sister Monica Joan is arrested for shoplifting.