It’s funny how the premise of a movie, the 30-second “elevator pitch” on the back of the box, can make you think the work within is good when it’s wretched or likely to be hackneyed when it’s amazing. Without cinema trailers, enthusiastic cast visits on Craig Ferguson and smoking-porch buzz the blurb is practically useless (unless it contains the word “erotic,” which always means an inadequate hamburger patty of a movie with sex used as beef heart and soy flour filler).

Take “Frozen River,” an hour and a half of poor people struggling in unfair desolation near the New York-Canada border. Elevator pitch? Ray (Melissa Leo), a poor upstate New York mother of two saving up for a double wide, stumbles into a friendship and business partnership with Lila (Misty Upham), a Mohawk woman (also trying to save up money to get back her infant son) smuggling people from Canada across a frozen river. The movie’s just an invitation to watch two people predictably destroy themselves and everything around them, right? Because if they turn a profit, that’s just condoning stuffing people in your trunk and breaking the law.

The center of emotional gravity in the movie comes after the shot of Ray’s bleary old tattoos, her unopened bottles of bright and cheaply cheerful bubblebath and the tub that looks like a badly stained Crock-Pot, the family dinner of Tang and popcorn, after Ray’s withering glance at her younger co-workers “How You Doin’?” tramp stamp and her last second skid home in the forest-green beater Dodge Spirit with the payment for the rent-to-own TV. It’s when they’ve gone to pick up two Chinese men and Ray learns that they each pay about $40,000-$50,000 to come to America, working it off cent by cent. “To get here?” Ray says, disbelieving. She repeats it. “To get here?” I’ve got it bad, she must think, but at least I don’t have it that bad.

Writer/director Courtney Hunt’s work doesn’t need to be propped up with comfortable cliché. Lila is overweight, with butch hair and no smile. Ray’s boys are adorable, sure, but the older one’s no Jonas brother (thank goodness). Ray is not secretly street-smart (she doesn’t ask for a receipt when depositing thousands on her double-wide) or have Lloyds of London-insured skin like Angelina Jolie. She has that tight, tired look that comes from never having enough money to fill up the gas tank and so little to lose that a few miles on 14-inch ice is worth it.

These are not the people who win — ever — even if they keep their heads down and just concentrate on the day job at the dollar store. At best, they only get excoriated by the haves for escaping into a pack of $2 cigarettes. But they, and “Frozen River,” are tremendous things of beauty, even in a desolately ugly time and place.