How can music that often takes such a critical beating exert so much influence around the world? That's the mystery and the magic of heavy metal, explored in this documentary that follows fan (and co-director) Sam Dunn on a continent-hopping journey to study how nations in Asia, South America, and the Middle East have tailored the aggressive and extreme genre to their own tastes. 90 min. Widescreen (Enhanced); Soundtracks: English Dolby Digital 5.1, Dolby Digital Surround stereo; Subtitles: English (SDH); audio commentary; interviews. Two-disc set.