As part of Opera on the BBC, choirmaster Gareth Malone is given the task of finding 50 teenagers from across East Sussex to sing on the main stage of one of the world's most prestigious opera houses, Glyndebourne. After rehearsing in a studio for two months, the Knight Crew company moves onto the main stage at Glyndebourne for the first time. Rehearsals continue with John Fulljames, director, blocking out scenes on set, and Nicholas Collon conducting in the pit. Unfortunately Gareth's young chorus cannot be heard at the back of the auditorium and he has his work cut out teaching them in the wings during breaks in rehearsals. As Knight Crew chorus master, Gareth is in charge of three choruses and he needs to find 15 mums to sing in the Mothers' Chorus. Who better than the mothers of his teenage chorus? After ringing around, a few mums are willing to have a go. Desi wants his mum Karen to get in, but is her voice good enough? As opening night looms there is a chance for a girl from the Knight Crew chorus to sing solo. Gareth holds auditions and picks 17-year- old Elsie, who has no experience and has never had a singing lesson in her life. It is a life-changing opportunity. After three music rehearsals the mums sing on stage for the first time and fall to pieces. Conductor Nick pans their performance, calling it 'musical carnage'. Gareth is under fire too when he conducts the backstage choruses and it goes wrong. It is the big night and nerves are high. The Knight Crew chorus must now step up to the plate and see if Gareth's months of training and nurturing can ultimately come good.