Mother Mildred decides it’s time for Sister Frances to attend her first solo birth. Trixie consoles a patient who discovers she has gonorrhea.

Jenny is seconded to a short-staffed hospital in London, but grows increasingly reluctant to carry out her duties when she finds out she is working under intimidating surgeon Mr Tracey. Back in Poplar, the midwives are introduced to newcomer Jane and outspoken twins Meg and Mave Carter. The sisters are identical in every way, except one of them is now pregnant - forcing them to come to terms with the impact a baby will have on them.

Nonnatus House prepares for the annual summer fête, but when a baby show is announced, the girls must find a host for the proceedings. Meanwhile, a patient of Jenny's puts her life at risk, and Sister Bernadette remains troubled.

The midwives face one of their busiest nights to date, whilst Sister Winifred concentrates her efforts on the prostitutes of Poplar. Elsewhere, cracks start to appear in Trixie and Tom Hereward's relationship.

The Nonnatus team rallies to support first-time parents Marie and Tony Amos when Tony is arrested for gross indecency with another male. Elsewhere, as Poplar is gripped by an outbreak of dysentery, Trixie undertakes her first official church duty since her engagement to Tom.

After the closure of Nonnatus House, the nuns and midwives finally move into their new premises. Sister Winifred arrives from the Mother House. Jenny is worried about new mother Merle’s mental state and the welfare of her baby who isn't feeding properly. Dr Turner is worried that it could be something more serious.

Tom, the local curate, asks Trixie to join him for a day of cricket. She accepts, but the date is disastrous. Shelagh decides to talk to Dr. Turner about adopting a baby. Patsy, struggling to adapt to the unpredictable and chaotic life that midwifery brings, upsets a young mother in the clinic.

Lucille helps elderly hoarder Clarice Millgrove who is struggling to keep her independence; Sister Hilda and the team work hard to help a Ghanaian family with an undiagnosed illness; Violet puts herself forward in the upcoming elections.

Valerie helps a struggling mother accept her son's birth defect. The Turners oversee a measles vaccination trial at the clinic as the team prepare for the Whitsun bank holiday.

The team tries to unite an estranged mother and daughter who are both pregnant. Trixie's friend is devastated to discover she is pregnant.

Demolition work in Poplar uncovers a long-buried secret that leads to a testing and emotional case for the team. Sister Julienne takes on a sensitive delivery.

At the monthly cytology clinic, Sister Frances comforts a young woman who is struggling with a life-changing diagnosis. Lucille supports a difficult mother.

Shelagh organises a special celebration to mark 100 years since the Order first arrived in Poplar - although Sister Hilda feels that she should have been in charge of the festivities. Nancy tackles the plight of meths drinkers living rough in Poplar, and Nurse Crane treats a young singer who is torn between two very different futures.

Sister Hilda and Dr Turner support a young father with a lung condition whose wife is planning a home birth, and discover he is also coping with the repercussions of a past trauma. Cyril looks for a job that will put his qualifications to good use, a first-time mother struggles to bond with her daughter, and Fred comes up with a way to keep the wards cool during a summer heatwave.

Trixie has been assigned to a complicated case involving a crane driver who was injured in a workplace accident and is now paraplegic. Meanwhile, Nancy and Sister Frances give a talk on the facts of life at a primary school, and Lucille's attendance at a straightforward delivery takes a distressing turn. Shelagh decides to organise a jumble sale to raise money to fix some broken playground equipment in the park. When Sister Julienne finds a suspicious item, chaos ensue

Sister Monica Joan seeks advice from a clairvoyant. Matthew is shocked to discover squatters in one of his warehouses, and Shelagh faces the most challenging delivery of her career.

Nonnatus House suffers its biggest threat yet. But this time it’s not the bricks and mortar that are in danger, it’s the people.

Sister Julienne calms an anxious new mother who has put her baby in danger. Jenny, seconded to The London, is impressed with the facilities, but soon begins to see cracks in the establishment. Chummy is upset to learn that her mother has walked out on her father, leaving Lady Browne penniless. As Dr. Turner and Shelagh continue the adoption process, they uncover a devastating secret.

Jenny is assigned to first-time mother Jeanette, who requires frequent visits during a protracted labour, and when she meets her patient's cousin, Philip, a new friendship begins to grow for the midwife. Meanwhile, Chummy worries about her mother's illness when she discovers Lady Browne has discharged herself from hospital.

A chance encounter with an impoverished child forces Trixie to see an unfamiliar darker side of life. As Nonnatus House welcomes a new resident, Nurse Barbara Gilbert, Tom Hereward has a surprise romantic gesture in store for Trixie.

The nuns and midwives are busy preparing for Sister Evangelina's surprise jubilee celebrations, marking 50 years since she took her vows, but a face from the past threatens to ruin the party for the guest of honour. It's back to business when a young woman with Down's syndrome is brought in feeling unwell. To everyone's surprise, they discover she is six months pregnant, causing some of them to think the worst, and the staff are joined by new nurse Patsy, whose sense of humour and no-nonsense attitude make her an instant hit.

Cynthia has to administer daily insulin injections to diabetic John Lacey, a bully who consistently belittles his wife Annie. When Annie’s beloved son Bob pays a visit, Annie gains the confidence to start to turn her life around. Jenny looks after a black mother to be, Monique, who is subjected to racial prejudice from her neighbours.

The convent comes under threat of demolition. Fred's pregnant daughter and her young son come and stay with him. Jenny is wooed by a new love interest. Chummy and PC Noakes prepare for the arrival of their baby.

Trixie's feathers are ruffled when Jenny is promoted, but the new Acting Sister has more to worry about after a mother-to-be reveals the baby she is carrying doesn't belong to her husband - and to complicate matters, the real father is black. Cynthia is inspired by a lecture on natural childbirth, convinced it will help an overly anxious patient, while Alec and his friends try to persuade Jenny to join them on a CND march.

Sister Julienne receives an SOS from Holloway Prison, whose usual maternity workers have been struck down by illness, and when she and Trixie step in to help, the nun puts her reputation on the line to prevent a heavily pregnant convict having her unborn baby taken away by social services. Shelagh faces heartache when a routine pregnancy check reveals something far more serious, Alec has a confession for Jenny and Fred takes the gang to the theatre to celebrate Chummy's birthday - only for the trip to end in disaster.