This career-spanning documentary about heavy metal legend Ronnie James Dio chronicles his incredible rise from 1950s doo-wop to his early classic rock days in Ritchie Blackmore’s Rainbow to replacing iconic singer Ozzy Osbourne in Black Sabbath and finally his legend as DIO. Ronnie’s biography is far removed from the sex, drugs and rock ‘n’ roll cliches. It’s a story of perseverance, dreams and the power of self-belief.