In spite of intense prize-in-the-eyes PR that includes a mega-celebrity charity auction plus the whisking to United Arab Emirates safety of its four young stars and a relative each, The Kite Runner is good for two-thirds of its 128-minute running time. This is largely due to the uncloying interpretations of those fourth- and fifth-graders from Kabul, one of which, Ahmad Khan Mahmidzada’s Hassan, The New York Times gushed, “ranks among the great child performances on film.”

The flip side is that, restructuring Khaled Hosseini’s best-selling 2003 first novel, the movie slides downhill after its fine portrayal of childhood bonds and cowardice in Afghanistan twenty-six years in the past. Flaunting improbabilities and toeing the administration and media’s black line on the Taliban -- who may well be that repulsive -- the final section, a framing 2000 San Francisco to Pakistan to Afghanistan, seems cut and cast in the mold of many a bring-‘em-back of the innocents from the jaws of worse-than-death and spirit them to family, freedom and fun. The screenplay by David Benioff “streamlines the novel’s narrative [and] simplifies the chronology” but loses the intimacy of the adult first-person narrator and published storyteller, Amir (Khalid Abdalla), and, sledgehammering home his late repentance and redemption, thumps its chest for the good-heartedness of Americans.

The descent into sentiment is exemplified in the self-satisfied last moments, straight-shooting at a family dinner followed by an Afghan New Year’s Day in Bay Area spring when Amir’s atonement is accepted as he repeats the words of the friend he once betrayed, “For you, a thousand times over.”

Amir’s first hardcover arrives from the publisher, “your baby,” says childless wife Soraya (Atossa Leoni). A Season for Ashes is dedicated, not to the recently deceased father (Baba, played by Homayoun Ershadi) who raised and sacrificed for him, but to that father’s wise friend Rahim Khan (Shaun Toub), who calls at that moment from Pakistani exile to insist that the new author “should come home, there is a way to be good again.”

Book tour canceled, flights arranged, the tale switches to the excellently imaged past. Liberal in alcohol and tobacco, a Pashtun businessman wealthy enough to air his open disgust with the capital’s extremists, Amir’s (ten-year-old orphan Zekiria Ebrahimi) widower father is devoted to his only child and to the servants, frets that the story-writing boy is unassertive and dreamy, and recognizes handwriting on the wall in the republic’s strengthening fundamentalism and intolerance.

Amir is inseparable from head servant Ali’s (Nabi Tanha) illiterate son Hassan, smaller but unquestioning in defending his friend and master with his body or his Davidic slingshot and unerring as a kite runner, that is, tracking down opponents’ grounded kites after their strings have been cut in the popular aerial combats for which Baba still holds the all-time record.

Young Assef (Elham Ehsas) and his street bullies pick on shy Amir and, a rumble of ethnic cleansing to come, fasten on defender Hassan as a pollutant inferior Hazara. Stung by a previous failure of nerve, the three older boys catch the latter in an alley in pursuit of a felled prize-winning kite. They extract revenge, in front of a cowering hidden Amir. The stoic bleeding victim says nothing, may or may not sense his companion’s cowardice, but withdraws into mourning for himself and for their relationship. In confused shame at what he has witnessed and his inability to help then or now, Amir multiplies his guilt with false story-telling.

Over Baba’s protests and orders, Ali and Hassan go away, and the wealthy anti-Communist father and son flee, too, at the Soviet invasion in September 1979. Admirable in protecting the boy and defying a rape-minded Russian frontier soldier (Vsevold Sevanchos), the once-sleek father maintains his dignity in failing health as the two drift to America, to work in a Fremont, California, gas station convenience store and an Antiques & Collectibles flea market. A community college graduate and aspiring writer, grown Amir is smitten with classics reader Soraya at a nearby stall, and in love when she confides that a story of his “made me cry.” The young woman has an unpleasant Virginia incident to confess and a snooty Pashtun father, former General Taheri (Qadir Farookh), whose consent must be obtained, but supportive Baba and love win out.

SPOILER ALERT

Which brings us back to the opening telephone summons, and to Peshawar, where a dying Rahim Khan will deliver a snapshot and letter from self-schooled Hassan, reveal a family secret from a “past [which] claws its way out,” and set the dubious writer on a mission. Not all that much of a surprise, the motivating secret metaphorizes religions’ and Walt Whitman’s “all the men ever born are also my brothers,” as it prompts Amir towards atonement in a sudsy rescue. Notwithstanding his giveaway accent and unfamiliarity, along with skin paler by several shades and fake beard, he enters, succeeds and gets out of heavily guarded Afghanistan, with the help of Sohrab’s (Ali Danish Bakhty Ari) slingshot. Such impossible odds echo Bronson in the boyhood friends’ memorized The Magnificent Seven.

That a single such gesture proves useless and harmful is voiced by practical orphanage director Zaman (Nasser Memarzia) and, in the more levelheaded Holly, by children’s aid volunteer Marie. The touchy-feely redeeming rescue allows for a tear and a pat on collective backs. But it also rose-colors issues and, in this case, betrays a film that promised better.

(Released by Paramount Classics and rated “PG-13” for disturbing thematic material including the sexual assault of a child, violence and brief strong language.)