An impressive first feature by writer/director Courtney Hunt, "Frozen River" boasts considerable suspense-movie tension and a compelling emotional journey for its foreground characters. Set in wintry upstate New York, the film finds a tone of no-nonsense naturalism and never loses it.

Melissa Leo, a longtime supporting player with a string of impressive credits ("21 Grams," "The Three Burials of Melquiades Estrada"), is impressive as Ray Eddy, an impoverished single mother facing the worst week of her life. Her gambler husband has vanished with the payment for their new trailer home, her 15-year-old son TJ (Charlie McDermott) is seething with resentment and her 5-year-old expects Santa to bring presents that Ray's salary as a dollar store clerk can't buy. Dinner consists of microwave popcorn and Tang.

What seems to be a maudlin tale of kitchen-sink gloom gradually takes the shape of a thriller. Ray goes in search of her no-account husband but finds his abandoned car in the hands of Lila (Misty Upham, who has a suggestion of a weary bulldog in her impeccably blank face). The Mohawk woman lives on the reservation that spans the U.S. and Canadian sides of the St. Lawrence River, its tribal sovereignty providing safe passage for smugglers.

Ray and Lila enter into a distrustful partnership chauffeuring illegal Asian immigrants into New York. Lila provides the know-how about evading police and Ray pilots the Dodge sedan whose trunk carries the human cargo. Over the course of several boarder crossings, Lila and Ray develop a wary affinity and even begin to recognize their Chinese and Pakistani passengers as kindred spirits.

The film has the ambience of a short story, not always in a good way. It wears its symbolism on its sleeve -- the icy river is a representation of Ray's repressed humanity, and Ray's auto is (nudge, nudge) a dilapidated Spirit. Still, there are moments of poetry on display. Throughout the film TJ stubbornly works to repair a junkyard contraption planted beside the trailer. When its function is finally revealed, it's a breathtaking little revelation.

And the film grapples with some thorny dilemmas: Aren't the immigrants whom Ray ferries into the country likely to become her competition for the lowest rung on the service-economy ladder? And the glimpses it gives us of lives lived on the precipice of poverty are sure and sharply observed, down to the bubble-bath soap that Ray hoards in anticipation of the day she acquires a tub.

As Ray and Lila travel across the slushy St. Lawrence, they seem to be fleeing forces larger than New York State troopers or sinister smugglers. People like them win small victories at best, which is exactly what the film delivers. There are stabs of suspense, though, mostly concerning children left unattended. You can feel the sentimental engineering that went into creating those sequences -- they're designed to tease and fulfill moviegoers' expectations -- but like the film as a whole, they are bracingly effective nevertheless.

Colin Covert • 612-673-7186