The nuns and midwives are pushed to the limit as they must tackle more heart wrenching cases in the community.
There will be a hard-hitting storyline as Sister Julienne (played by Jenny Agutter) meets widow Mabel, played by Anita Dobson, and discovers her dead husband’s hidden abuse.
Sister Julienne must try and keep the family together as secrets threaten to tear them apart.
Jenny, 64, revealed in an interview with TV Times: “We can deal with hard issues because there is a sense of redemption that is uplifting. It reminds us that community is important.”
This year’s special will be set against the backdrop of the 1962 Big Freeze, which saw one of the coldest winters on record for the UK.
The weather is a huge hindrance as the Poplar residents struggle in the arctic conditions.
Doctor Turner actor Stephen McGann said: “Everything runs down, the milk can’t be delivered and their normal world has turned into a disaster, but they’ve still got their job to do.”
Newest recruit Valerie Dyer (Jennifer Kirby) must contend with the cold as she helps out a young expectant couple who are living in a caravan.
Linda Bassett, who plays Nurse Crane, said: “It is very Christmassy and a bit like a modern manger because they don’t have a proper home and it is freezing.”
However, there will still be festive fun in Poplar as Barbara and Tom Hereward (Charlotte Richie and Jack Ashton) throw themselves into helping with the community pantomime.
The special episode will lay the ground for the seventh series of the show which is expected to return in early 2018.
Call The Midwife Christmas special will air at 7.40pm on Christmas Day on BBC One.
The full interview with the Call the Midwife cast can be seen in the latest issue of TV Times.