Take a BBC period drama, a bustling convent, a stream of newborn babies and what do you get? It can only be Call The Midwife.

The beloved TV series, which is now firmly considered a national treasure, follows the adventures of the midwives of Nonnatus House throughout the 50s and 60s as they welcome new lives in London’s East End.

Every year since 2012, however, the medical drama has gifted viewers an extra bundle of joy by way of its annual Christmas special, now a jewel in the crown of the BBC’s festive lineup. This year is no exception, as the nuns and nurses of Nonnatus are back on their bikes supporting the community in Poplar, with an added sprinkling of tinsel for good measure.

In this year’s edition, we’ve time-travelled back to December 1966, where good tidings are in the air. On the countdown to Christmas, the festivities are in full swing: Fred Buckle is dashing about dressed as Father Christmas, Reggie’s in his Christmas jumper hoping for snow, and Miss Higgins and Nurse Crane are putting on the Sunday School nativity. Naturally, there’s a real baby in the manger.

Meanwhile, preparations for Lucille and Cyril’s wedding on Boxing Day are underway. Initially, there’s a little friction between the nuns and Lucille’s extended family, who are set on sticking to Jamaican customs. But later on, Sister Hilda tells Nancy with a gleam in her eye that she’ll be throwing a hen night for Lucille complete with “party games, fruit punch and a selection of savoury snacks”.

Of course, things rarely go smoothly during the Christmas period, especially when babies are involved.

Over at Nonnatus House, Nurse Crane informs the midwives that they’ve been assigned 20 extra patients from St Cuthbert’s Hospital. And, you guessed it, most of them are due on the run-up to Christmas. Trixie looks startled at the impending chaos. Nurse Crane sweeps out of the room with a dramatic parting shot: “If I believed in God, I’d be praying for a miracle”.

In the busy clinic, there’s also trouble brewing in the form of a young mother-to-be, Anita Page, who’s underweight and very resistant to examination. Sister Julienne is concerned about anaemia and goes to call Dr Turner; but when she returns, Anita has run off with no explanation.

We soon find out the reason for the young woman’s condition when she takes heroin in the laundry room at her apartment block. It seems as though the men in her immediate circle are also involved in substance abuse; later on, Dr Turner receives an emergency call at the surgery and has to attend to a man suffering from acute opiate intoxication.

In the world of Call The Midwife, however, every expectant mother-to-be receives the same level of exceptional care and attention from the midwives, no matter their circumstances. And so, when Anita staggers to Nonnatus House after her waters break, Nurse Crane and Miss Higgins jump into action and drive her to the maternity home, where Trixie is on hand to help her deliver a baby girl.

It’s immediately clear there’s a problem: the baby is severely underweight and crying incessantly. And Anita, who’s now suffering withdrawal symptoms, doesn’t want to feed or bond with the baby either.

Come Christmas Day, and things only get more complicated at the maternity home. Overwhelmed, Trixie calls Dr Turner and asks him to drive over and assist with some of the difficult cases. His first port of call is Anita, who opens up to him about her addiction, just before her baby begins fitting. Sadly, it turns out that the tiny newborn is addicted to heroin, too.

It’s a very good moment for Mother Mildred to arrive on the scene. After rolling up to Nonnatus House on the back of a milk cart, the indefatigable Mother Superior examines Anita’s baby at the maternity home. She tells Shelagh and Dr Turner that she knows exactly what medication the baby needs, and how to administer it, for she’s seen many cases before while she was working abroad in Hong Kong.

Mother Mildred agrees, with a touching endorsement. “The measure of love needed,” she tells Shelagh, “you already know”.

Back on the maternity wing, Anita confides in Shelagh that her mother was an alcoholic, and was in the care of the welfare office when she was a child. Shelagh tells Anita that what matters now is caring for her baby, inspiring Anita to bond with her daughter. Later, spurred on by Shelagh’s words, Anita opens up to her husband Charlie about her addiction, and they resolve to try their best for their newborn.

Meanwhile, Dr Turner informs Shelagh that she’ll get the chance to nurse Anita’s baby back to health when she is taken to the Children’s Hospital. It’s an emotional moment when Shelagh tells him that it will give her the chance to “travel back in time”, and care for the baby in a way that she was unable to do for May.

As the nuns and midwives all return to Nonnatus House, where Mother Mildred is entertaining the children with a spirited reading from A Christmas Carol, we’re reminded of the power of community. By pulling together, the nuns, midwives and friends of Nonnatus House have seen off a slew of challenges, saving both the festive celebrations and protecting the most vulnerable individuals in their society from harm. What’s more, their unwavering care and attention has actually enabled individuals like Anita to stop hiding and be their true authentic selves.

By the end of the programme, Lucille and Cyril make it down the aisle, surrounded by their nearest and dearest. It’s at this precise moment that the narrator imparts a beautiful message about the nature of community.

“Family may be sacred, but community has a holy dimension of its own,” she intones. “Blood is never the own thing that binds us; it is often the ties we choose that have most power. Love connects us all like links in the finest chain, like ribbon around roses; like the weave of thread in the fine white cloth.”

It’s fitting, too, that Nurse Crane has assembled a very special group of bridal attendants: all the boys and girls that Lucille has helped deliver since arriving in Poplar. Their mothers, she tells Lucille, have vowed they’ll always remember Lucille’s support during their deliveries.

As we come to the end of another challenging year, it’s a poignant reminder that healing, contrary to popular belief, rarely happens alone. But when a community folds you in its patient, loving, non-judgemental embrace, we are very often able to pick up the pieces and move on with our lives.

Call The Midwife Christmas Special is available to stream now on BBC iPlayer.

If you are struggling with addiction, Samaritans (116 123) operates a 24-hour service available every day of the year. If you prefer to write down how you’re feeling, or if you’re worried about being overheard on the phone, you can email Samaritans at jo@samaritans.org.

Images: BBC