Featuring concert footage and interviews with stars and fans, the second of director Penelope Spheeris's documentaries about the Los Angeles music scene focuses on heavy metal, the raucous genre that has provoked controversy since the late 1960s. With her penetrating questions about sex, drugs, money and gender politics, Spheeris examines the lives of rock idols Ozzy Osbourne, Paul Stanley and Steven Tyler, as well as those of their devoted fans.