In London, a 90-year-old sings the Frank Sinatra classic that gave him back his voice after he had a stroke. A 15-year-old performs an original tune about growing up Black in Britain. An 83-year-old from Derry sings a song that she gave up 30 years ago because it made her daughter cry, and a father and son perform the lullaby that's always been their song.

Sam Ryder and Paloma Faith take the chosen singers into the studio to rehearse for the final concert. But first, they decide to include a fifth singer. Who should they bring back? As the practice sessions begin, Milo must learn to be bigger on stage, Chantel battles with self-doubt, Findlay rehearses his mum's funeral song a year after her death and Mina starts losing her voice the day before the concert. Alison Hammond follows their progress.