The Canadians are here to save us. Metric are the latest in a long line of bands -- The Arcade Fire, Broken Social Scene and The New Pornographers among them -- that have reintroduced Americans to the beauty of melodic guitar rock. Like their Canuck contemporaries, Metric take rock 'n' roll to a smarter, more sophisticated place than do most of today's American bands.

Live It Out takes a sophisticated approach to punk rock, mixing its raucous melodies with ambient sounds and slow, ghostly pauses. Opener "Empty", for instance, begins with ethereal synths and singer Emily Haines's longing keen. After two minutes, Nirvana-style guitars crash, Haines sings louder and the music kicks into a truly propulsive groove.

Most of Live It Out bears a mild resemblance to Broken Social Scene's more chaotic tunes, so it's no surprise that Haines's show-stealing vocals featured prominently on the wonderful BSS rocker "Almost Crimes". Here, she proves herself to be amazingly versatile, shifting effortlessly between "Glass Ceiling"'s minor key musings and "Too Little Too Late"'s tender earnestness. Jimmy Shaw's guitar stays perfectly in step, whether it's shaking in ecstatic fits or slowly picking out a lead line.

Eventually, "Police and the Private" brings Live It Out to an abrupt halt. After earning our attention with unrelenting rock, Metric completely switch gears, putting Haines front and center over a bizarre, wandering keyboard line. It proves to be a perfect move; she cuts through the mannered keyboard fog with the album's best melody line, singing, "Lord lord mother, we are all losing love."

Live It Out is full of longing, anger and emptiness. Sex lies around every corner, and often turns to violence, as it does in "Too Little Too Late": "Sure for the first time you're wearing the right clothes / Now take them off / Meet me on the band room rug / Tie my right hand to the ride." That violence invariably points to power struggles and feelings of helplessness -- familiar feelings, if not sources of particular pride. Metric are fighting for their freedom, even as they ask others to tie them down. Their struggle culminates in "Police and the Private"'s childish plea: "Lord, listen, lover, we are all missing mama." Doesn't it always come down to basic human needs?

Other Canadian imports may have outshined Metric in the past, but they're clearly ready to make some noise of their own. Once again, it falls to Canada to remind us just how powerful rock 'n' roll can be.