Gareth Malone forms a choir with the partners left behind by troops away in Afghanistan.

In Plymouth, Gareth is overwhelmed by eager new recruits for his choir of military wives.

Choirmaster Gareth Malone believes singing can help people through the most difficult times of their lives. Gareth has been invited to RMB Chivenor Military base in north Devon, where the troops are about to deploy for a six-month tour of duty in Afghanistan. While the troops are away, Gareth starts a choir with the wives and girlfriends who've been left behind.

With the choir proving such a success at Chivenor, Gareth decides to start a new choir at a base in Plymouth, whose troops are suffering fatalities out in Afghanistan. Gareth has to manage emotions that ride high as the two choirs struggle to combine, and then he has to persuade them that they are good enough to sing together.

Finally singing as one choir, Gareth sets the Chivenor and Plymouth military wives the biggest challenge of their lives: to perform at the Royal Albert Hall on Remembrance Sunday. The women contribute letters and lyrics to a song that is specially created for them by royal wedding composer Paul Mealor.

After a six-month wait, and agonising reports of multiple injuries and fatalities on the frontline, the choir members' husbands finally return, to joyous reunions. Now Gareth has to make sure his choir members give it their all, for the once-in-a-lifetime Royal Albert Hall performance.

In February 2011 Gareth Malone went to the military base at Chivenor to set up a choir for the wives who are left at home alone while their men are on duty for months at a time.

We hear from Gareth and key members of the choir as they reflect on their extraordinary journey culminating in their performance of a song specially written by Royal composer Paul Mealor at the Royal Albert Hall. This seemed like the pinnacle of their achievements - but the film shows how this was the beginning of something much bigger.

We see the women as they embark upon launching what was to become a number one Christmas single, as they visit 10 Downing Street, perform at the Golden Jubilee and then win a Classical Brit. We also discover the legacy of the choir with the establishment of a charitable foundation that provides the support for a growing network of over 60 military wives choirs in bases across the UK, Europe and the Falkland Islands.