IN THE TITLE ROLE of Rosetta, Emilie Dequenne has one of the most remarkable walks in movie history. Hunched over as if battling the wind, her arms either stiff at her sides or stuffed in her sweater pockets, she hurtles forward so quickly you keep expecting her to break into a jog. There's something mechanical about her breakneck trot, the insistent clomps of her feet; or there would be if you didn't notice the quick, birdlike jerks of her head and eyes, constantly checking to make sure no one's following her. Rosetta seems capable of outpacing anyone -- even the camera, which struggles to keep up with her at the film's opening, only to have doors constantly slammed in its face.

Dequenne effortlessly handles any dramatic requirements the script demands of her (remarkable, considering she'd never acted before), but I'm convinced it's that walk that's largely responsible for the well-deserved raves she's gotten from critics, and for the award she received at Cannes. That walk just seems so tiring -- indeed, Rosetta is constantly sucking water from a plastic bottle, and her sharp breaths and trampling feet are often the only sounds we hear. If she gets weary, though, she never shows it while in motion, maintaining her implacable march and touchingly skittish side-glances. Whether she's hunting down the man who promised her a job, or racing across her trailer park to demand that the manager turn on the water and stop plying her alcoholic mother (Anne Yernaux) with booze for an easy lay, or avoiding Riquet (Fabrizio Rongione), the young waffle-stand employee who fancies her -- there's the same headlong rush of movement.

Steely focus and a hardened carapace that just barely fails to conceal a humane fragility -- that's Rosetta, both the character and the film, and neither make it easy for you to admire them. The hand-held camera creates a cramped intimacy, but we are allowed only fleeting glimpses of characters' inner lives. Details irrelevant to the film -- Riquet's history, the source of Rosetta's stomach pains -- are left hanging, while minutes go by watching Rosetta poach fish or exchange her shoes for waterproof boots when she takes a woodland shortcut home. Though these solitary minutes flirt with tedium, they are key to the film's success. When Rosetta interacts with others she's abrasive, accusing, even vicious; watching her alone we learn of Rosetta's drive, her intelligence, and how bravely she's dealt with obstacles. People aren't what they say, but what they do. Rosetta understands that as well, which is why her driving quest throughout the film -- to get a job -- is so moving.

After years of making documentaries, the brother team of Luc and Jean-Pierre Dardenne recently moved to fictional films. Their remarkable first feature, La Promesse, used the accidental death of an illegal immigrant to examine in thorough detail a young man bridling under the conflicting obligations of family and morality, conscience and self-preservation. Rosetta represents an advance, insofar as the Dardennes have managed to include all of those concerns (and more) in the story of an 18-year-old girl looking for employment.

Such a commonplace goal, but for Rosetta it's all encompassing. Money's a part of it -- a large part to be sure. When she sells off some mended clothes to a store, she bargains so nakedly you know how much she needs the cash. That she derives more than a paycheck from her employment, however, is clear from the scenes we see of her at work. Suddenly the stern desperation is gone from her face, and she is responsive and quick to learn. She's good at her job, even to the point of smiling if it's required; and in return she gets treated like an equal for once. Her worth is validated, an outcome unlikely to ever occur with the mother Rosetta must scold like a child, or the unseen neighbors at the campsite. At one point, when a job and even a new friend seem secure, Rosetta lies in bed whispering reassurances to herself; now, she insists, I have a normal life. However, there can be high prices to pay for normalcy.

Rosetta's determination can be off-putting, as can the movie's elliptical style or the jittery nervousness of the camerawork, but it's worth sticking with. The film ends with the same shot that has dominated throughout: hovering around Rosetta as she walks. Only this time she can barely keep moving forward, and finally she collapses, as if the exhaustion she'd been shrugging off the whole of the movie hit her all at once. Without the previous 90 minutes, the moment would be uneventful; but when it comes, you realize how tender and compassionate the movie has been toward its withdrawn heroine all along, and how much she's deserved it.