Bev Bevan explores the origins of heavy metal music and Black Sabbath's homecoming gig, with interviews and music from Black Sabbath, Judas Priest and Slipknot. As the music stops, fireworks go off above Villa Park as the founders of heavy metal bow out of their unbelievable career.

Ozzy Osbourne took his final bow after reuniting with the original lineup of Black Sabbath to play a farewell concert before a crowd of over 40,000: 'Thank you from the bottom of my heart.'

Black Sabbath reunited for the first time in 20 years at their farewell show, Back to the Beginning, on July 5, but it wasn't without some drama.