The definitive account of a heavy metal band in full self-destruct mode is, of course, 'This is Spinal Tap', a spoof that feels as true as it does absurd. And the prospect of a documentary about a crisis in real-life band Metallica brings hopes of something similar. But the truth revealed by this long documentary is as dull as it is surprising: that the band, far from being ageing wild men, are middle-aged businessmen deep into a culture of therapy; As someone who is not a fan of the music, it's interesting to see how singer James Hefield is clearly a man of considerable vocal talents, and not just a wild screamer; but when he tells you he drives a roadster to indicate that he's a rebel, he could be any forty-something desperate to convince himself of this fact. In the middle of the film, he checks into rehab to help recover from alcoholism, which is potentially a powerful story. But on camera, we never see him drink a drop, and only get to witness the endless, self-absorbed discussions and ego-trading with his fellow band members that seem indicative of a group that lacks the urgency, need or desire to actually achieve anything beyond bickering about their places in the group's internal pecking order. The film's only value comes in exposing this; for if this is truly rock and roll, then rock and roll is dead.