This documentary from Bruce Sinofsky and Joe Berlinger (HBO's Paradise Lost films) follows heavy metal band Metallica through the two tumultuous years it took to produce its 2003 album St. Anger. The band has lost a bassist, but gained a therapist: It's your chance to be a fly on the wall, not for all the fabled debauchery of rock 'n' roll, but for the heavy emotional lifting offstage which ends up being more interesting than another round of booze and boobs. The film plays a bit like Spinal Tap in therapy, but beyond unintentionally funny scenes of band mates Lars Ulrich and James Hetfield parsing through "I" and "we" statements, there's an illuminating portrait of a mega-huge band falling apart under its own weight, and then, surprisingly, working hard to put themselves back together with a minimum of artistic compromise. A must for fans, but well worth a look by all. Two devil's horns up.