Jenny befriends an old soldier named Joe, and is disturbed by his living conditions. She is also visited by a man from her past, while Trixie and Cynthia have a sensitive case to deal with, and Chummy is asked on a date.

A new baby is snatched from her pram, sparking an area wide search. Jenny is more familiar with the kidnapper than she realizes, Cynthia blames herself when a patient becomes gravely ill, and Chummy's romance continues.

A figure from Jenny's past makes contact, while Jimmy continues to pursue her. Chummy prepares for an important meeting, and everyone at Nonnatus House rallies round the building's cleaner, Peggy, whose brother is very ill.

Jenny speaks to her ex-lover again, while Sister Monica Joan lands herself in trouble with the police. Chummy receives a visit from her snobbish, imperious mother which forces her to reconsider her relationship with Peter.

Chummy makes an important decision, Jenny reconnects with Jimmy, and Cynthia's conduct is called into question after the death of a baby she delivered.

Hesitant nursing assistant Jane Sutton arrives at the convent as Jenny is seconded to hospital work, meeting Jimmy, who, to her surprise, is one of the patients. Arrogant surgeon Aubrey Tracy misdiagnoses Jimmy and an operation is required, where Jenny acquits herself well. She also sees that Tracy is himself ill and he resigns. Meanwhile aggressive twins Meg and Maeve Carter - both married to the hen-pecked Sid - arrive at the clinic as Maeve is pregnant. However they eschew modern medicine for old herbal remedies and, following a bleak tarot card reading, the over-bearing Meg scares her sister into refusing hospital admission. Ultimately Maeve senses that she needs professional care and allows the midwives in for a home birth - where a new generation of twins is born.

Sister Bernadette is discharged from hospital, while a heavily pregnant Chummy resumes her midwifery duties. Jenny meets a new love interest, Fred's pregnant daughter pays him a visit, and Nonnatus House itself is under threat.