This is a joke, right?

That's the initial thought during the first few minutes of "Anvil! The Story of Anvil," a winning and surprisingly moving documentary about — wait for it — a struggling Canadian heavy metal band that apparently influenced a generation of hard-rockers, including Metallica, Anthrax and Guns N' Roses.

OK, if they're so crucial, why aren't they more well-known? Are you sure this isn't some Spinal Tap-like slice of performance art masquerading as reality?

Nope, it's all true. The band was on the cusp of making it big in the early '80s, recording three albums well-regarded by the metal underground and opening for acts like Bon Jovi. But bad luck and bad decisions dealt a knockout blow to those rock 'n' roll hopes.

Yet founders/childhood friends Steve "Lips" Kudlow (guitars/vocals) and Robb Reiner (drums), now in their 50s, have kept the Anvil spirit alive for more than 30 years. They'll play anywhere, from small bars in suburban Toronto to near-empty rock festivals in Transylvania.

It's an often thankless task, made even crueler by club owners who refuse to pay up and family members who want them to grow up. While their determination may not be realistic — if fame hasn't happened in three decades, chances are it's not going to — it is refreshingly infectious.

"Anvil!" is less about music (it's actually beside the point, as not that much of it is heard in the movie) than the power of friendship through tough times and not letting the world beat the life out of you. By the end, director Sacha Gervasi — one of the original Anvil fans from the '80s — has turned Kudlow and Reiner from caricatures of music-industry desperation and woulda-coulda-shoulda hopelessness into characters worth rooting for. Liking heavy metal is not a prerequisite for enjoying this movie.

But even metal-haters might find themselves headbanging to Anvil's anthemic "Metal on Metal" and considering ordering some Anvil discs online. After all, if the music doesn't speak to you, the dreams sure will.