Harry is a twelve-year-old autistic boy, who also has ADHD. His father, David, has sole custody of Harry. David's ex-wife, Laura, had a breakdown due to the stress of bringing up Harry. David takes time off to spend some time with his son, but struggles to cope with Harry's behaviour. To add to their anxiety Harry will be singing at the Royal Festival Hall as part of a special needs group, even though he hates singing and people clapping too loud. Will he be able to hold it together in front an audience of two and a half thousand?