Melissa Leo, best known for her work on the standard-bearing cop show Homicide: Life on the Street, gives a memorable performance as a tough, working-poor mother in upstate New York whose financial problems push her into smuggling illegal immigrants from Canada to the U.S. across the frozen Saint Lawrence River. The debut feature of writer-director Courtney Hunt, this is steeped in the soul-crushing details of life below the poverty line: cutting corners, scratching around for cash, fending off bill collectors with sweet talk and pathetic lies. But it’s also a first-rate thriller, maintaining a high level of suspense as the mother and her sullen Native American partner (Misty Upham, also excellent) navigate between suspicious police and ruthless black marketers. R, 97 min.