Written and directed by Luc and Jean-Pierre Dardenne, La Promesse is the story of a 15-year-old boy whose act of adolescent rebellion is taken in the name of contrition and kindness rather than in a stance of defiance and cruelty. Though we are never told this, we suspect that Igor (star-in-the-making Jeromie Renier) is himself the son of an immigrant. At any rate, his father, Roger (Olivier Gourmet), is now involved in smuggling illegal aliens into contemporary Belgium and setting them up with falsified residency papers and work permits. This is a story of rank exploitation. New to the country, the immigrants live in sordid, poorly ventilated and ill-heated rooms in a housing complex Roger owns and manages. He pays them slave wages to work for him and occasionally betrays a handful of his wards to relieve pressure from corrupt city officials.

Igor (Jeromie Renier, right) longs to be carefree, but he must face the realities of the world in La Promesse.

In part, we see that Igor is just a child, a typical teen interested in hanging with his friends and building a go-cart. But Igor is also Roger's primary lieutenant. Igor is supposed to be studying auto mechanics under an apprenticeship program, but he's forever skipping out of work to assist his father. In so doing, he's made friends with a number of Roger's boarders. He seems particularly connected to a black man named Amidu (Rasmane Ouedraogo), whose wife, Assita (Assita Ouedraogo), and baby son have just arrived from their native Ghana. When Amidu is injured in a fall from a scaffold at one of Roger's building projects, Igor tries to save him and beseeches his father to rush the dying man to the hospital. But Roger refuses because he fears that investigating authorities will topple his entire illegal immigrant operation. It is not clear that Amidu could be saved. Probably not, in fact. But Roger's indifference registers with Igor even as he accepts his fathers orders and ultimately helps bury Amidu in concrete. But before he dies, Amidu elicits a promise that Igor will look after Assita and their child. To do so, Igor must defy his father, who quickly devises plans to send Assita off to Germany (perhaps into a life of prostitution).

Not everything holds together here. I don't know what we're supposed to make of Assita's seeking (and receiving clues about) Amidu's whereabouts in smears of chicken entrails, and in an African seer's studies of shells thrown over smoothed sand. Elsewhere, Roger's determination to trick Assita into going to Germany seems needless given her desire to go to Italy on her own. But most important, the film doesn't motivate Igor's transformation with enough clarity. When we first meet Igor, he's stealing the pocketbook of an elderly woman living on a pension. Subsequently, the Dardenne brothers never establish a clear catalyst for Igor's conversion. It's true that his father is a brute, but Roger and Igor have the kind of relationship that more often leads to reactive abuse syndrome than to redemption.