The holiday season fuels desperate action in Frozen River as well. It’s nearly Christmas in Massena, N.Y., a working-class town that borders Canada on the St. Lawrence River and includes a Mohawk reservation. Ray (Melissa Leo) has been saving for a down payment on a double-wide, which arrives as scheduled—only Ray’s husband, an addict and gambler, made off with the cash the day before. Her 5-year-old, Ricky (James Reilly), tearily runs after the truck as it takes their new home away. Her 15-year-old son, T.J. (Charlie McDermott), pissily reiterates his offer to start working and asks if Ray is even going to bother looking for his dad.

She’s at least going to look for his car, which is where she stashed the money. Ray finds it, but not him, at the reservation’s bingo hall, and when she sees a Mohawk woman, Lila (Misty Upham), get into the car and drive away, she follows her to her trailer. Lila laughs at Ray’s threats to call the cops, saying they have no jurisdiction on the self-governing res. But she tells Ray that she knows a guy who’ll buy the car, who’s always looking for vehicles with pop-open trunks. Warily, Ray lets Lila direct her across the iced-over St. Lawrence: “This is so fucking stupid,” she says, but the lure of a couple thousand bucks trumps her fear.

The potential buyer doesn’t take the car off Ray’s hands but does shove some money into them, along with a couple of illegal immigrants who are ushered to the trunk. Across the border, they get more cash and unload their haul. Lila reassures Ray that it’s not a crime because the “trade” is between Mohawk lands. Then she says something more believable: “They’re not going to stop you; you’re white.” Each trip means a relatively easy $1,250, more than her dollar-store job probably pays her a month.

Writer-director Courtney Hunt’s debut is starkly photographed and quietly taut, avoiding sentiment or sensationalism in favor of an engrossing story. Some of its themes are familiar—poverty, racism, single mothers desperate to support their families—but Frozen River’s focus on two female protagonists, both unflinchingly flawed and human, is rare and refreshing. Besides the obliviously optimistic Ricky, who wraps Christmas lights around himself and waits for Santa to come, no character is all good or all bad. Ray always shows up for work and pushes for a promotion, and though she feeds her kids popcorn and Tang for breakfast, she does feed them. Lila has a year-old son that the tribal council took away from her after her smuggler husband died; she sits in a tree outside her mother-in-law’s to watch her child and smuggles herself so she can leave money outside their door. Even T.J. is no saint: His “classmate” offering a job is actually a guy for whom T.J. steals credit-card numbers. Still, it allows him to buy his little brother a Christmas present when Mom’s too busy breaking the law to get to Kmart in time.

Leo and Upham give terrifically nuanced performances with characters who are prickly at their sunniest, both bossy and mistrustful of other races. (When Ray is asked to drive two “Pakis,” she says she’s never even heard of Pakistan and hopes “they’re not the ones who blow themselves and everyone else up.”) But their drive and resolve, especially when things go wrong, are too admirable to dismiss them as cold opportunists. And, of course, there’s the love they show their kids. You shouldn’t want to cheer when a criminal uses dirty money to save the family flat-screen from the repo man just in time, but Frozen River hooks you into imagining that Ray’s struggles could be your own.