The news that Hollywood was making a film about the slaughter of Wall Street Journal reporter Daniel Pearl at the hands of Al Qaeda sent a shiver down the spine. His kidnapping while on a story in Pakistan and his subsequent beheading, caught on videotape for propaganda effect, followed by the discovery of his dismembered body, suggested a mess of inappropriate images matched to a crude, crass morality tale.

There was little reassurance that something good would come of the idea when it became known that the project had been adopted by Hollywood’s first couple, Brad Pitt and Angelina Jolie. Mr. Pitt has co-produced the movie, “A Mighty Heart,” and has cast his girlfriend as Pearl’s wife, Mariane. The result is a great surprise. The film is an extraordinary testament to the existence of the war on terror — for those like John Edwards, who suggest it is a mere Bush bumper sticker — and a reminder of the soulless brutality of the enemies we face. It is a remarkable tribute to the business of journalism and the dangers reporters face in trying to bring new facts to their readers.

There are few heroics in “A Mighty Heart.” British director Michael Winterbottom’s film is shot in documentary style from a screenplay that suggests considerable improvisation from the cast. Daniel Pearl, played by Dan Futterman, is portrayed as a regular guy, an ordinary, earnest journalist who has found love in someone who can understand the vagaries of his routine because she, too, is a working journalist.

Ms. Jolie, sans makeup, barely lit, and devoid of the quotidian glamour that informs her life both on and off the screen, plays Mariane Pearl mostly in a deadpan. Heavily pregnant with their first child, her character wanders as if in a daze. Apart from expressing the odd expletive when frustrated by the slowness of the investigation, there are no histrionics. The true response of this most prominent victim of terror is one of numbed horror only occasionally leavened by memory flashes of their courtship. Only when she is told of Pearl’s demise with the wretched euphemism “Danny didn’t make it” does she wail a long, loud primal cry of pain — a terrible, haunting sound only echoed when she delivers her baby son Adam in the maternity ward.

The movie is taken from Mariane Pearl’s account of her husband’s disappearance and Mr. Winterbottom does not appear to have tampered with the truth. All the familiar elements of life in the subcontinent are here: the clamorous chaos of the streets, the ubiquitous cellphone culture, public officials divided between the impressively efficient and the wretchedly inept. The paranoia of Pakistan is wonderfully caught, with the minister of the interior accusing Pearl’s assistant of being an Indian spy rather than acknowledge that his country is at all levels riddled with ambiguity toward the West and smothered by corruption.

At the premiere on Thursday night at the Ziegfeld in Midtown, the film was presented under the auspices of Amnesty International and Reporters Without Borders in support of those like Pearl who risk their lives trying to make sense out of the senseless. Pearl’s abductors and executioners were finally caught, but not through the painless application of science as found in “CSI” but through the Pakistani authorities adopting the tactics of the terrorists: brute force, abduction, and torture. The film serves as a persuasive reminder that the war on terror is being fought a world away from the uniformed warriors and battle conditions for which the Geneva Conventions were first conceived.