Call the Midwife returns this Christmas with Sisters in Arms, a three-part BBC One prequel set in wartime Poplar, East London, in 1939. The series follows the nuns and nurses of Nonnatus House as they fight to preserve lives when explosives fall on the area during the Blitz.
The festive special will not continue from the most recent season, which was set in 1971. Instead, the period drama turns back the clock to World War Two, featuring younger versions of Sister Monica Joan, Sister Julienne, and Sister Evangelina, alongside new characters.
What is Sisters in Arms about?
As the Blitz intensifies, Poplar is devastated and circumstances become extremely challenging. The National Health Service and welfare state do not yet exist, so when war commences, it is the personnel at Nonnatus House who courageously serve their community, assisting babies, mothers, and anyone requiring help.
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 continues: "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 features in Sisters in Arms?
Created, written, and executive produced by Heidi Thomas, Sisters in Arms introduces a fresh ensemble. Coronation Street's Julie Hesmondhalgh, known for playing Hayley Cropper, stars as Sister Alice. Stage actress Helena Wilson takes on the part of a younger Sister Julienne, while original actress Jenny Agutter provides narration for the miniseries, and Helen Schlesinger portrays Sister Monica Joan.
Ami Metcalf, who appeared as Lynette in the inaugural Christmas special, returns as Betty Buckle, Fred Buckle's first wife, with Fred now portrayed by Ciaran Bowling.
The cast list for Sisters in Arms includes 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, and Bally Gill as GP Dr. Kit.
When will Sisters in Arms air on BBC One?
Production has concluded on Call the Midwife: Sisters in Arms, with Heidi Thomas revealing behind-the-scenes insights. "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 broadcast on BBC One and iPlayer this Christmas, although the precise dates and timings have yet to be announced. Call the Midwife was previously broadcast on Christmas Day 2025 at 8:15pm with a repeat showing on Boxing Day at 8:30pm.
