Featuring the country's best a cappella groups performing popular songs like you've never heard them before. There's no lip-synching, backup bands or safety net. They'll be singing for America's vote, with the winner walking away with the ultimate prize - a Sony Music recording contract and $100,000.

Gareth Malone searches for Britain's most entertaining amateur singing group, in a music contest with a difference - groups must sing a cappella.

Follows the real life stories, high stakes and personal triumphs of the country's top competitive collegiate a cappella teams as they battle it out to win the ICCA Finals.