Call the Midwife is returning to BBC One this Christmas with Sisters in Arms, a three-part prequel set during World War Two, taking place in 1939 as explosions devastate Poplar, East London, and the nuns and nurses of Nonnatus House fight to save lives.
The period drama, which debuted in 2012, will not continue from season 15, set in 1971. Instead, the prequel features younger versions of Sister Monica Joan, Sister Julienne, Sister Evangelina, Fred Buckle and Dr. Turner, alongside several new characters.
What is Sisters in Arms about?
Sisters in Arms will see Poplar destroyed as the Blitz strikes, making existence extraordinarily challenging. With no National Health Service or welfare state, the personnel at Nonnatus House courageously assist their community by supporting 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?
Developed, penned, and executive-produced by Heidi Thomas, Sisters in Arms introduces a fresh ensemble, featuring Coronation Street actress Julie Hesmondhalgh as Sister Alice. Stage performer Helena Wilson assumes the part of a younger Sister Julienne, while the original performer, Jenny Agutter, will provide 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, the first spouse of Fred Buckle, now portrayed by Ciaran Bowling.
Here is the cast list for Sisters in Arms: 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?
Filming has wrapped on Call the Midwife: Sisters in Arms, with Heidi Thomas sharing behind-the-scenes secrets. "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 the 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. Call the Midwife is available to stream on BBC iPlayer.
