L’Enfant, the latest trip out to society’s margins from the masterly Belgian team of Luc and Jean-Pierre Dardenne, begins, as all their films do, in media res. After the opening credits, we see a teenaged girl march up the stairs of a miserable building and deliver angry kicks to an apartment door. She’s also holding a baby.

Her name is Sonia and we learn that she’s just returned from the hospital where she gave birth to her child, and now she’s discovered that her boyfriend has sublet her apartment in her absence. After some inquiries, Sonia locates Bruno, her boyfriend, as he plies his trade of panhandling and petty theft. Her anger quickly disappears under the glow of motherhood and she shows Bruno their baby. He looks with minimal curiosity, as if the baby were someone else’s, before he takes a phone call from a criminal accomplice.

Those of us with less than a smattering of French would naturally assume that “l’enfant” is the French for “baby,” but it literally means “child.” And the child of the film’s title, we learn from this opening sequence, is not the baby in Sonia’s arms but the callow, careless father who won’t look at his newborn son.

With this beginning, L’Enfant makes a feint in the direction of a diatribe against the scourge of petty criminals who double as deadbeat dads, but this film, fortunately, is the work of filmmakers who have devoted their careers to exploring the terrible moral choices faced by society’s most vulnerable members. In La Promesse, the film that first brought them international acclaim, a young boy must decide whether to turn his father, a trafficker of human beings, in to the authorities. Their next film was Rosetta, in which a desperately lonely, nearly feral young woman struggles to hold a job, finally having to choose between unemployment and betraying her only friend. Rosetta earned them the Palme d’Or at Cannes, and they followed up in 2003 with Le Fils (The Son), which concerned a teacher at a reform school who is obliged to mentor the boy who’d killed his son.

Clearly, if you’re looking for a date movie you’ll want to steer clear of les freres Dardennes–unless, of course, your date is interested in the intersection of old-fashioned cinematic realism and Christian parable. But for those who are excited by cinematic realism and raw moral drama, the Dardennes are the most outstanding filmmakers plowing the fields once tilled by the likes of Robert Bresson, Carl Theodor Dreyer and Roberto Rossellini.

In L’Enfant, Jérémie Renier plays the hopeless punk Bruno like a boy who takes sugar, caffeine and nicotine as a way of coping with ADHD. (The Dardennes break from the rather dogmatic notion–from Bresson–that social realism must be enacted with non-professional actors. Renier is a professional who got his start as the child-hero of La Promesse.) Despite Bruno’s unpromising introduction, he defies our expectations. For starters, we learn that, far from being a violent brute, Bruno is actually quite harmless–physically, anyway. He’s almost a creature of literature, the amoral drifter of Celine, Genet, Henry Miller and Jack Kerouac who lives in defiance of bourgeois norms.

When Sonia (Déborah François) suggests to Bruno that he take a handyman job that a social worker had offered him, he snorts, “Only fuckers work.” At that moment, Sonia spots a motorcycle jacket in a store window that matches exactly the one that Bruno wears. Without a moment’s hesitation, Bruno peels off some ill-gotten bills and buys one for Sonia, who puts it on with a squeal. It’s a relationship of innocent outlaws–another staple of European cinema in the 1960s and 1970s–and Bruno wears a fedora that recalls the look of New Wave stars such as Léaud and Belmondo. He lives from one moment to the next, never planning anything more than a few hours in advance. But a baby makes things different, and this is what Bruno learns–eventually–in L’Enfant.

In the film’s inevitable plot hook–and single most dreadful scene–Bruno does what he does every day when he needs cash: He looks around for a source of it, and on this particular occasion he has been left alone with the baby. So he sells the infant–with only the slightest of second thoughts–so he can pay his debts to the 14-year-old thieves in his gang and live another day.

The film doesn’t tell us how the baby black market works, or what kinds of people buy babies. Instead, we just get a single, street-level look at one deal going down, in a scene that is horrifying in its sinister banality. Bruno is directed by cell phone to a vacant apartment and instructed to leave the baby in one room while he waits in another. Without cutting away, the Dardenne brothers show the look on Bruno’s face as he listens to the baby hustlers entering and leaving the next room. A minute later, Bruno finds 5,000 euros in the spot on the floor where his baby had been.

It’s ugly stuff, but what is refreshing–exhilarating even–about a movie like L’Enfant is that it doesn’t recoil in horror from Bruno and his deed. In America, our 24/7 media culture is heavily dependent on exploiting the depths of human misery and error. When a mentally ill woman drowns her children in a bathtub, the media leads the lynching party against this agent of unspeakable evil. But in the films of the Dardenne brothers, people who do depraved things are not beyond redemption or understanding. In L’Enfant, there’s no question that Bruno has done a terrible thing by selling his baby, but the Dardenne brothers want to know why he did it, and how Bruno accepts his obligation to put aside childish things and become a man.

Those who have seen this year’s Oscar winning foreign film Tsotsi will notice a certain congruence in the storylines. Tsotsi dramatizes the story the journey to personhood of a violent young South African thug who accidentally kidnaps a baby. But why is Tsotsi such a chore to sit through, while L’Enfant earns the right to our undivided attention? The difference comes mainly from the method of telling the story. Tsotsi is more movie than reality, full of over-designed sets, artificial movie dialogue, heavy-handed flashbacks and sentimental symbolism. There is, in other words, a thick coat of conventional artifice and grime between the story on the screen and the audience.

L’Enfant isn’t the best film by the Dardennes–that distinction belongs to Rosetta (indeed, L’Enfant recycles several motifs and episodes from that film, including a near-drowning). Furthermore, the Dardennes are justly famous for their perfectly timed endings, but the final scene of L’Enfant feels more forced than earned. Still, these are quibbles–this latest effort from the Dardennes is an effectively devastating variation of what it is to be young, poor and alive.