Adam Hart-Davis sets out on a rare musical quest: to get to the bottom of the strange world of 'tuning'. Why do we need tuning? Is there any correct way to tune a musical instrument? And does it really matter? Along the way, we clamber into the bowels of a cathedral organ, meet the inventors of some rather unusual musical instruments, and discover whether even the most sophisticated recording technology is up to the job of making Adam Hart-Davis sing perfectly in tune.