At first it’s easy to mistake “Anvil: The Story of Anvil” as another mockumentary in the “Spinal Tap” mode—surely the fact that the drummer in the heavy metal band it profiles is named Robb Reiner is a dead giveaway. But no: this is a serious picture about a real group. And it’s a surprisingly amusing and moving one.

The picture begins a full quarter-century ago, with footage from a 1984 concert in which Anvil appeared alongside the likes of Whitesnake and Bon Jovi and seemed poised to go to the very top; there are also comments from players in long-established bands who testify as to how great, and influential, the youthful Anvil was. But cutting to 2006, we find original lead singer Steve “Lips” Kudlow and drummer Reiner toiling away at workaday jobs in their native Toronto (Kudlow’s is at a caterer that delivers to schools), desperate for small-time gigs at clubs with their newest guitarist and bassist (having gone through multiple players in each slot). And they’re trying to put together material for a planned thirteenth album, even though they’ve long lacked a big-label contract and their discs, since their three big early hits, haven’t gotten much attention.

Most of “Anvil” follows Kudlow and Reiner as the fifty-year olds try to keep their dream of rock fame alive while maintaining relatively normal home lives with their families. First they’re off on a European tour put together by a well-meaning but hopelessly inept fan named Tiziana Arrigoni, who repeatedly flubs travel arrangements and can’t even secure payment. (She comes across as a pathetic figure, though, rather than as a scam artist. And there’s a nice twist on her story in the final credits.) Then the plot turns to that thirteenth album, which a noted British producer agrees to make if the guys can raise the funds (something Kudlow manages to do in a poignant scene, though his efforts as a telemarketer prove hilariously ineffective). The resulting sessions illustrate the occasional blowups that occur in the Kudlow-Reiner relationship, as well as their continuing friendship; and when the record is finished, finding a distributor proves an impossibility.

But even while the men suffer setback after setback, their dedication continues—though it’s constantly challenged. And through their own reminiscences we get to know a lot about how the band began and the early successes it had (as well as observations from their families that are sometimes not entirely supportive). And in the end, just as it seems that their hopes are going to be dashed yet again, there comes a surprise invitation to a rock festival in Japan where, despite fears that the crowd might be small, the concern proves groundless.

You can pigeonhole “Anvil” if you like, saying it’s simply a fable that teaches us all never to abandon our dreams. But that unjustly reduces it to a tagline. It’s a deeply human piece that’s hilarious one moment and touching the next. You certainly don’t have to be a fan of Heavy Metal to appreciate this affectionate but revealing tribute by Sacha Gervasi (who, as the final credits also show, has been a fan for a long time).