In these, the last days of summer, two great thrillers about smuggling and moral ambiguity, both set in cold places, go head to frosty-eared head. Both are well worth seeing in the theater. But it’s the one that less people are certain to see that’s really something special.

First up, there’s Transsiberian, a solid Hitchcockian thriller set aboard the Trans-Siberian Railway. Directed by Brad Anderson (The Machinist), Transsiberian stars Woody Harrelson as Roy, a twerpy train-aficionado and happy-go-lucky American tourist, and Emily Mortimer (Lars and the Real Girl) as Jessie, an amateur photographer with a bad-girl past. The couple, after completing some church-based nonprofit work in China, head to Moscow along the famous rail line. Once aboard, they befriend Abby (Kate Mara) and Carlos (Eduardo Noriega), an edgier, sexier couple as signified by Abby’s thick eyeliner and Carlos’ even thicker Spanish accent.

Things, of course, are not what they seem, and Anderson has fun keeping the audience guessing as Roy and Jessie are pulled into an adventure that embrangles drug smugglers, really bad Russian service (!) and a menacing narcotics detective played by Ben Kingsley. In sum, Transsiberian—even while it feels fairly familiar—is a well-acted (particularly by Mortimer and Kingsley), tightly-scripted and suspense-filled thriller.

Tight spaces are always conducive to creating suspense and, while Anderson makes good use of the narrow train passages in Transsiberian, first time filmmaker Courtney Hunt, in her indie-thriller Frozen River, creates a similar miasma of unease using a different sort of claustrophobic atmosphere: poverty. Her central characters, Ray (Melissa Leo) and Lila (Misty Upham), white and Mohawk respectively, are two impoverished mothers who live on the frozen, desolate borderland between New York state and Quebec, Canada. Ray is forced to feed her two sons popcorn and Tang for dinner, after her gambling-addicted husband absconded to blow the balloon payment for their double-wide trailer on bingo or craps or who-knows-what. Lila is a petty criminal and an outcast on the rez who sleeps alone in a tiny trailer after her child was taken from her according to some tribal custom. They are both trapped in the devastating cycle of poverty, which seems to present only bad options.

And so, what at first feels like a stark, ultra-cinema vérité indie, eventually morphs into something entirely more nerve-wracking as Ray and Lila form an uneasy alliance of necessity. The pair begins smuggling Chinese and Pakistani immigrants across the rez. Lila’s got the connections in Canada and can traverse the somewhat lawless reservation; Ray’s got the pop-trunk Dodge Spirit and, because she’s white, she’s less likely to be stopped by the police once they’re off the rez.

Hunt’s low-budget, though beautiful, highly naturalistic cinematography, along with the low-key, incredibly realistic performances of both Leo (21 Grams) and Upham (a fairly unknown but terrific native actress who gained 40 pounds for the role), help create the sense that one has been transported into a completely real world and into very real lives. Also adding to Frozen River’s naturalism is that the MacGuffin of money—in contrast to Hollywood films such as Transsiberian in which the sum is usually intended to impress—is simply in the hundreds. This is money of survival.

Hunt brings out this theme of survival-while-poor splendidly through two motifs: the literal traversing of thin ice and the omnipresence of people gambling who clearly have next to nothing. Few middle-class people fully understand the risks that people living on the edge—without back-up or support—are forced to take. Frozen River—the best of this pair of good thrillers—makes this anxiety palpable.

Frozen River
Written and directed by Courtney Hunt
With Melissa Leo, Misty Upham, Michael O’Keefe, Mark Boone Junior and Charlie McDermott
UA DeVargas, 97 min., R

Directed by Brad Anderson and written by Brad Anderson and Will Conroy
With Woody Harrelson, Emily Mortimer, Kate Mara, Eduardo Noriega and Ben Kingsley
UA DeVargas, 111 min., R