Call the Midwife is returning to BBC One this festive season with a three-part prequel series titled Sisters in Arms, set during World War Two in 1939 Poplar, rather than a traditional Christmas special following the latest series set in 1971.
The period drama, which has aired 15 series since its 2012 debut, will rewind the clock as bombs rain down on Poplar, East London, with the nuns and nurses of Nonnatus House battling to save lives. Sister Monica Joan returns as a younger incarnation, alongside Sister Julienne and Sister Evangelina in the early stages of their careers, joined by new faces.
What is Sisters in Arms about?
Sisters in Arms sees Poplar reduced to rubble as the Blitz takes hold, with no National Health Service or welfare state in place. When war breaks out, the staff at Nonnatus House serve their community, helping babies, mothers, and anyone in need.
A BBC synopsis reads: "In September 1939, Sister Monica Joan is in her prime, Sister Julienne and Sister Evangelina are young and zealous, and Nonnatus House is the beating heart of Poplar. Together with Sister Alice, and local GP Dr Kit, the nuns dedicate their lives to mothers, babies and those in need. But there is no gas and air, no penicillin, no cure for TB, and no welfare state. Then war is declared – and life gets even harder."
It adds: "The three young secular midwives who complete the team – Sybil, Olive and Marianne – receive a baptism of fire as the blackout and the Blitz take hold. While bombs rain from the sky, women give birth underground, families are shattered, children run wild, and whole streets are reduced to rubble. But courage, compassion and resilience triumph as the community unites in its efforts to survive."
Who is starring in Sisters in Arms?
Created, written, and executive produced by Heidi Thomas, Sisters in Arms welcomes a new cast, including Coronation Street's Julie Hesmondhalgh as Sister Alice. Theatre star Helena Wilson takes on the role of a young Sister Julienne, with original actress Jenny Agutter narrating the miniseries, and Helen Schlesinger plays Sister Monica Joan.
Ami Metcalf, who played Lynette in the first Christmas special, returns as Betty Buckle, the first wife of Fred Buckle, now played by Ciaran Bowling.
- Julie Hesmondhalgh as Sister Alice
- Helen Schlesinger as Sister Monica Joan
- Amy Booth-Steel as Sister Evangelina
- Ami Metcalf as Betty Buckle
- Ciaran Bowling as Fred Buckle
- Helena Wilson as Sister Julienne
- Lizzie Back as Sybil Maxted
- Ellie McKay as Olive Dobbs
- Liv Andrusier as Marianne Siegler
- Ben Rose as Dr. Patrick Turner
- Bally Gill as GP Dr. Kit
When will Sisters in Arms air on BBC One?
Filming has wrapped on Call the Midwife: Sisters in Arms, with Heidi Thomas sharing behind-the-scenes details. "Call the Midwife has a long and noble history of filming Christmas specials during heatwaves, and this year we welcomed the snow-machine back to the Nonnatus House set like an old friend," she said. "But I was surprised how many new emotions Call the Midwife: Sisters in Arms sparked. In particular, the evacuation of Poplar's children, and the fear that they may not make it home for Christmas, had us all in tears."
The BBC has confirmed Sisters in Arms will air on BBC One and iPlayer this Christmas, though exact days and times are yet to be confirmed. Call the Midwife previously aired on Christmas Day 2025 at 8:15pm followed by a second sitting on Boxing Day at 8:30pm.
