Perhaps the finest band on a very, very fine Canadian label, Constellation Records, Silver Mount Zion returns with 13 Blues for Thirteen Moons, their first record since the near-masterpiece Horses in the Sky.

Released in 2005, that record established Silver Mount Zion as a musical force all its own, existing beyond any sort of stylistic boundaries.

On their follow-up, the band luckily, remarkably, continue to grow, evolve, and get even better.

Things start in a deceptively familiar fashion on "1,000,000 Died to Make This Sound" (which is billed as track 13, preceded by 70 seconds of random, high-pitched sounds divided into 12 short tracks) strings are plucked quietly, a choir is singing softly, and Efrim Menuck enters with his usual quivering vocals, until some three minutes in, when everything quietly fades away.

And then it starts for real.

After a brief pause, the whole band kicks in with an astounding, utterly unexpected fervor and volume, and the song is immediately transformed into a huge, soaring rock anthem reaching up to the skies.

Frankly, it's quite a thrill to hear Silver Mount Zion kick up a maelstrom of sound like that; simply put, they have never rocked that hard, or that convincingly, in their entire career.

Even the noisiest, loudest moments of Godspeed You Black Emperor! never hinted at such fiery abandonment.

Those sonic explosions were always incredibly tight and precisely controlled, whereas this new noise of Silver Mount Zion possesses an unpredictable, dangerous edge.

It's their call to arms, if you will, and if the band were to truly go out on the streets with this music, it'd surely present a matter of worrying for whatever establishment they'd choose to rally against.

It's only fitting that during the preceding tour, where Silver Mount Zion road-tested much of this material, the title track -- an ugly, raging beast of a song known as "We Just Want Some Action" -- could well stand as the title of this whole collection.

Such a shift in sound can even be perceived as a political statement of sorts, embodying a collective voice of people who used to be quiet and keep to themselves but are now unable to remain silent and intend to inform the powers that be that they are not going to take it any longer.

Whatever that "it" might be -- ongoing war, oil prices, poverty, hunger, social unrest, signs of Apocalypse -- it's really beside the point; what matters is a simple act of first raising your head and then your voice and your fist.

It's not all sound and fury, of course.

There are enough quiet moments amidst all the chaos.

"1,000,000 Died to Make This Sound" ends with a gracefully restrained coda, and 13 Blues for Thirteen Moons comes down from its truly aggressive start to a contemplative middle section only to build to another explosive climax, twice.

Still, even as the band tries to play it quietly, the noise comes insistently bubbling to the surface, as in the more traditionally Silver Mount Zion-esque "Black Water Bowled/ Engine Broke Blues." The closing "blindblindblind," meanwhile, starts quietly and is almost lovely, and then builds to another raucous finale, only this time the band sound not angry or rioting, but uplifting and almost rapturous.

And perhaps that's the most singular achievement of 13 Blues for Thirteen Moons, how the band known for its relentlessly bleak and desperate outlook manage to maintain enough spirit to close its most righteous, furious record on a note that's full of grace, beauty, and hope.

Silver Mount Zion were already way ahead of many of their contemporaries, but 13 Blues for Thirteen Moons sees them blazing past even further, up and away, to some unexplored, perhaps dangerous, but tremendously exciting new horizons of artistic expression.

It might be not really safe to keep up, but it's impossible not to.