There’s a melodramatic center to Joshua Marston’s debut feature, about a young–and pregnant–Colombian girl who becomes a drug courier to America in order to break out of her hopeless life at home. But the tale is told so skillfully, in a naturalistic, quasi-documentary style that’s well sustained throughout, that the picture leaves behind any hint of soap opera. By avoiding mawkishness on the one hand and sensationalism on the other, “Maria Full of Grace” emerges as a remarkably moving and affecting treatment of a subject that, if pumped up in typical Hollywood fashion, might easily have descended into TV-movie cliche.

Maria is played with unforced honesty by Catalina Sandino Moreno, a luminous, dark-haired young woman making her film debut. Seventeen years old, Maria works long, difficult days at a flower plantation, removing the thorns from the stems of roses to help pay household expenses for her grandmother, mother and sister, the last a single parent with an infant given to health problems. She’s also expecting a child by her careless, immature boyfriend (Wilson Guerrero), who says he’ll marry her although he admits he doesn’t love her and has no prospects in their rural town. It isn’t long before the unhappy young woman is approached by a smooth-talking cyclist (Jhon Alex Toro) from the capital, who offers her a job as a drug mule–someone who will swallow capsules filled with heroin and transport them in her stomach to New York. Under the pretense of looking for a maid’s position she goes to Bogota and, after talking things over with Lucy (Giulied Lopez), a woman who’s already made the trip, accepts an offer from a supplier named Javier (Jaime Osorio Gomez), only to find that her hometown buddy Blanca (Yenny Paola Vega) has done so too. The narrative shows Maria consuming more than sixty of the capsules and then follows the three women to JFK, where they have to make their way through customs–Maria is delayed by suspicious officials for a close examination, and a fourth courier is actually apprehended–before being taken to a motel by the local dealers to collect the merchandise. When Lucy suffers the dire consequences of a capsule breaking open in her stomach, Maria and the reluctant Blanca take the drugs and escape to the city, finding refuge through a ruse with Lucy’s sister Carla (Patricia Rae) and her husband. They’re eventually introduced to the unofficial “mayor” of Little Colombia, Don Fernando (Orlando Tobon), an avuncular man known for helping arrange the return the bodies of couriers who have died back home. Maria also takes steps to protect her family from reprisal back in Colombia and her unborn child as well, and in the end reaches a decision that, one hopes, will mean a better life.

What’s striking about “Maria Full of Grace” is the way it manages to remain beautifully direct while generating enormous emotional impact. Nothing is exaggerated or italicized. When Maria and Juan discuss their relationship, there’s a disarming casualness to their conversation, despite the serious subject. Javier isn’t portrayed as a sadistic monster, but as a rather soft-spoken businessman who grows threatening only when he explains the importance of Maria’s completing her contract. The customs officers aren’t harsh or unfeeling, but professionals doing a difficult job with as much courtesy and respect as possible. Lucy’s family members and Don Fernando are gracious and generous members of what seems a close-knit community. Even the New York drug dealers aren’t as brutal as one might expect–indeed, in the end they ever pay off their debts, however reluctantly.

Of course, the most remarkable character is Maria herself, and in the hands of Moreno and Marston she emerges as courageous and resilient, but not a plaster saint. It’s a splendidly written role, and Moreno plays it with quiet intensity and control. The remainder of the cast are equally fine, with Vega, as the frightened but curiously willful Blanca, and Tobon, who’s in effect playing himself, coming across especially well. The realistic, unobtrusive look of the picture is entirely in keeping with the restrained dramatic approach.

“Maria” is indeed full of grace, both as a character and as a film.