Gareth has decided he wants them to write their own lyrics for a brand new song. Some struggled with learning the lyrics last time - will they be able to cope with this challenge?The song-writing process challenges the choir to dig deep into their experiences of injury or illness and the different stages of recovery they are each in. Gareth struggles with his own emotions after hearing one of the choir's own experience of war and Gareth wonders if he, Gareth, is mature enough to cope with this whole mission.Next Gareth brings the choir back to London to St Martin In The Fields to sing them the finished song. It's a key moment as the choir hear the lyrics of their own stories. Once the choir is happy with the song Gareth decides to show the lyrics to a special industry friend.Throughout it all, Gareth is desperate to find out how to help them release their emotions when singing. For one member of the choir, Gemma, the experience is life-changing. Gareth worries that some choir members are struggling to cope with the process and if they will be able to perform in front of such a large audience. To help with this, Gareth takes them on an outing to an unusual venue for a choir!Before they set off to the US Gareth calls the choir to a recording studio and finally, the choir set off to the US. It's their big moment - will they be able to perform one final duty?