The eponymous heroine of Joshua Marston’s stunning debut feature Maria Full of Grace is a pretty 18-year-old who, when the film begins, works a boring job de-thorning roses at a flower plantation in provincial Colombia. The movie’s early scenes are brisk and flavorful in sketching the routines and other people in her life, but there’s one moment that stood out particularly as I looked back on Marston’s introduction of Maria (Catalina Sandino Moreno). She and her good-looking but rather vacant boyfriend, Juan (Wilson Guerrero), are locked in an embrace, kissing, in the shade of a building that’s under construction. After Maria’s eyes open and glance upward, she casually slips out of Juan’s arms and rapidly clambers up the building, like a kid up a tree. When she reaches the top and its expansive view, she calls down and urges him to come up. But Juan, exasperated, tells her she’s crazy and stalks off. His departure doesn’t seem to bother Maria in the least.

From this scene we infer a few immediate and rather obvious things about Maria and Juan, including that they are of very different temperaments and that their relationship is on a downhill slope. But what struck me later was how much it tells us about Maria apart from her romantic situation. That movement of her eyes, announcing the impulsive climb, seems to sum up not just her personality, but her spirit, her dreams, her intention. Indeed, the movie could be titled She Looked Up.

Not coincidentally, the same action is featured in the image used in the movie’s ads. There, Maria gazes upward as if about to receive Holy Communion, except that the round white object descending toward her mouth is not the sacramental wafer but a condom filled with cocaine. Maria will swallow dozens of these in Bogot and board a plane to New York, becoming an illicit narcotics courier–a “drug mule”–in an effort to escape a humdrum world where otherwise she’ll be condemned to low wages or enforced domesticity for life.

The ad’s image flirts with blasphemy in order to point up the real sacrilege: that many in the impoverished south are obliged to look up to rich, drug-addicted North America as a potential savior. The type of exchange implied in this look, the same exchange that impels Maria to trade her home’s suffocating safety for mortal danger in New York, is a grand and terrible symbol of a world riven by obscene inequities. And that is, of course, the largest subject dramatized by Maria Full of Grace. But to assume that it is the only subject would be to miss the point of that early scene noted above (the same point, in fact, made in the film’s wonderful final scene, which I won’t disclose): Finally, the movie isn’t just about the drug trade, or the damage caused by hedonistic gluttony and the unequal distribution of wealth, or any other issue you care to name. It is also about Maria, whose individuality refuses all pat classifications.

That’s another way of urging you not to make the mistake I did in almost passing up the movie, thinking, “Oh great, another earnest, well-intentioned social-problem film.” Maria Full of Grace may well be one of the rare American dramas currently that stems from a profound social conscience, and one moreover that comprehends the world beyond American shores. Yet it is also, in a way that must be seen to be fully appreciated, an astonishing feat of filmmaking on every level–a triumph that extends down to its smallest moments and details, and that will surely win it an armload of “best debut feature” awards at year’s end.

Let us greet writer-director Joshua Marston, then, at the beginning of what bodes to be a brilliant career. Watching his film reminded me of encountering the early work of talents like Scorsese, Malick and Coppola back in the early ’70s. That’s a compliment that verges on extravagance, I realize, yet Marston is a singular young director for inviting it. The reasons he does only begin with how commandingly he inhabits the tradition of realism that has always been at the core of American cinematic achievement, both classic and modern. Beyond this commendable aesthetic inclination, Marston’s work shows that he possesses, more than simply formidable talent and daring, a genuine vision of the world and cinema’s place in it.

For a neophyte director, it was a nervy move to set half of his first feature in a foreign culture. But the challenges facing Marston–a California native and recent graduate of New York University’s filmmaking program–went beyond the merely cultural. Political turbulence in Colombia made it an inadvisable place to film, so he and his mostly Colombian crew re-created Maria’s Colombian village in Ecuador. The scenes in the United States, which occupy the film’s second half, were shot on location, mainly in Manhattan’s Jackson Heights neighborhood. The movie has received understandable compliments for the accuracy of its depiction of both cultures, but there’s something more than just a thirst for authenticity at work here; more subtly, there’s also a desire for truth.

Maria’s truth, above all. Marston reportedly interviewed more than 800 actresses and was on the verge of postponing his shoot when he received a tape of Catalina Sandino Moreno, an aspiring actress and university student from Colombia. He says he realized instantly that she was the woman in his script. Yet that recognition merely laid the groundwork for an extraordinary collaboration between director and actress that obviously set the tone for the expertly naturalistic performances Marston elicits from a cast composed of both experienced actors and newcomers.

Maria Full of Grace is a film of subtle yet remarkably rich textures–human, cultural, emotional and visual. Thanks to the beautifully nuanced colors and handheld fluidity of Jim Denault’s exemplary photography, it pulls you in sensually from the first moments. And from then on, there are dozens of details in every scene that further the spell. Yet I decided, on seeing the film a second time, that Marston’s signature is noticeable especially in one element–the way the characters look at each other.

I can’t recall when I’ve seen a film that made such eloquent use of eyes. This is most true of Maria, naturally. In the early scenes, we see her at work at the dreary flower plantation; in the cramped home she shares with her mother, grandmother, older sister and the sister’s baby; and with Juan and her other friends. In all of these passages, the dialogue is admirably direct and idiomatic. Yet far more expressive and revealing are the gazes that Maria uses to negotiate her world. They’re like a silent language, and as we learn to pick up its meanings, we’re more and more able to read her feelings no matter what she says.

One crucial conversation with Juan offers a prime example. She tells him that she’s pregnant. Clearly unhappy at the news, he suggests marriage. She scoffingly asks where they would live. His family’s place is too crowded, and Juan is too macho for the indignity of living with his wife’s family. But more to the point: Does he love her? He snorts and looks away. Maria goes through the verbal motions necessary to finish this conversation, but in the way she looks at Juan, you can tell how little she thinks of him, and how disgusted she is at her own situation.

That disgust leads her to Bogot and an eyes-open encounter with the drug trade. It’s important to note here, though, that Maria is not desperately poor. She doesn’t live in a shanty town; her family is middle-class by Colombian standards. This is noteworthy because Marston shows us throughout that Maria’s actions blend exigency and choice.

In the city she also meets Lucy (Guilied Lopez), a smartly dressed if rather distant young woman who’s had a couple of experiences as a mule. Maria’s eyes glom onto her with an avidity that exceeds even her searching questions. What’s it like? How do you do it? Maria has good reasons to be nervous. The job is fraught with dangers. Lucy trains her to swallow the rubber-shrouded bags of coke by having her practice on grapes. If only one of the bags breaks, she dies. And if any bags fail to show up at the trip’s end, she may be killed.

It happens that Maria shares her journey with several other women on the same mission, including Lucy and Maria’s best friend from the village, plump, moon-faced Blanca (Yenny Paola Vega). The flight and the interrogation at U.S. Customs are gut-wrenchingly tense, but what happens afterward is even more harrowing. I won’t reveal it, except to say that Maria and Blanca, throwing themselves on the mercy of Lucy’s family in New York, find themselves in a world that’s at once dizzyingly perilous and strangely alluring.

American cinema, like the nation itself, is founded on immigrant stories, but none in recent years has been as culturally astute or artistically potent as Maria Full of Grace. When Marston’s consummately delicate film is over, you realize that you’ve glimpsed not only some of the darker reasons people still take enormous chances to reach these shores, but also the way one young woman has chosen to envision her future. In this provocative, quietly surprising fusion of collective and individual imperatives, there is indeed a kind of grace–the kind that belongs only to the most assured and insightful of filmmakers.