A cowardly Afghan boy grows into a man who must bravely return to his Taliban-ravaged homeland in The Kite Runner, Hollywood’s latest ode to atonement. Unlike the new film that’s actually titled Atonement, director Marc Forster’s adaptation is equal to its source novel—which is to say that it goes wrong at the same point that Khaled Hosseini’s novel does.

The story opens in 2000 in San Francisco, where Amir (Khalid Abdalla) and his formal but benevolent father (A Taste of Cherry star Homayoun Ershadi) have taken refuge after the Soviet invasion of Afghanistan. But the film quickly rewinds to 1978, when Amir is a boy (Zekiria Ebrahimi) living in Kabul. An upper-class child, Amir lacks nothing important except his mother, who died during childbirth. His closest companion is Hassan (Ahmad Khan Mahmoodzada),

the son of a household servant and a member of a despised ethnic minority, the Hazara. Hassan is the title character, blessed with a supernatural ability to find kites downed during battles involving glass-barbed strings.

Hassan accepts his low status and is fiercely loyal to Amir. And though Hassan is smaller than his companion, he’s the fighter of the two. In a scene that’s been well-publicized—the child actors had to be removed from Afghanistan because of the outrage over it—Hassan is beaten and raped by the local bully while Amir helplessly watches. Shamed by his weakness, Amir turns on Hassan, and the boy and his father leave the house. Soviet troops arrive soon after, and Amir and his father flee the country.

Years later, Amir is an aspiring writer who’s settled down with his wife, Soraya (Atossa Leoni), when he’s summoned to Pakistan by an old family friend: “There’s a way to be good again,” the man informs Amir. Hassan is now dead, and his young son, Sohrab (Ali Danesh Bakhtyari), is suffering in an Afghani orphanage. Amir is reluctant to enter Afghanistan, but then he learns some family secrets. So he hires a driver, dons a fake beard, travels to Kabul, and locates Sohrab. The deprivations and cruelties of Afghanistan under Taliban rule are vividly evoked. But Amir’s rescue of Sohrab was implausible in the book, and it’s even less believable in the movie’s compressed, less bloody telling. Amir’s quest is supposed to be a dangerous ordeal, but it’s resolved so easily that the film’s climactic sequence undercuts the film’s seriousness.

Mostly shot in a part of western China that borders (and resembles) Afghanistan, The Kite Runner effectively conjures the country’s dry, mountainous terrain, as well as a culture now crushed by invasion, civil war, and religious fanaticism. Forster (whose best previous film is 2004’s Finding Neverland) wisely establishes an authentic sense of place by using local languages and employing mostly Afghani and Iranian actors. He and scripter David Benioff (25th Hour) are also extremely faithful to Hosseini’s bestseller, even lifting large chunks of dialogue from it.

That deference to the novel (and its fans) is ultimately the film’s principal limitation. Both the movie and the book lose their authority after the childhood section concludes. Of course, the tale would be a hopeless downer without the shot of redemption that its final developments provide. But The Kite Runner might have been more persuasive if its makers had risked deviating from Hosseini’s plot to find an ending that’s truer to the world so deftly rendered in the novel’s first half.