On Sept. 4, 1969, the U.S. ambassador to Brazil was kidnapped by Brazilian radicals hoping to publicize their cause and secure the release of more than a dozen political prisoners. Four Days in September is a microscopic examination of that event and, just as importantly, the people involved in it.

At the center of the whirlwind is Ambassador Charles Elbrick (Alan Arkin), a distinguished veteran, accomplished diplomat and devoted husband who's been assigned the ugly task of representing America's interests in a nation in the grip of a military junta. The junta has imposed martial law, cracking down on demonstrations by students like Fernando Gabeira (Pedro Cardoso), who consequently joins the only opposition party he can find -- the October 8th Revolutionary Movement, or MR8.

But life isn't good for the MR8. The junta has cracked down so hard on the media that even a major bank heist doesn't garner press attention. So the group opts for a bold plan by Gabeira to kidnap Elbrick and offer to swap him for 15 political prisoners.

The plan works, but not as well the movie.

Four Days in September is a rare thing: a highly intelligent thriller that focuses as much on the people involved as on the events they involve themselves in. Director Bruno Barreto gives viewers enough time with each of the principals to allow us to see the kidnapping from his or her point of view.

Moreover, the script, based on a memoir by the real-life Gabeira, avoids turning the hostage situation into an us-against-them struggle. Instead, Barreto and Gabeira give us three, maybe four, sides to the kidnapping. And by the time the kidnapping and the fallout from the kidnapping are over, viewers have at least some sense of what everyone involved in the event has gone through -- even the junta's professional torturers.

In small but ingenious ways, Barreto reveals the finicky Elbrick as an astute and articulate observer, studying the hands of his captors to learn more about them and making some offbeat observations: "I simply cannot believe," he says, "that I am going to die in an empty room, unshaven, wearing wrinkled, sweaty clothes."

Elbrick is the kind of off-center character Arkin plays best, and he's at the top of his game here.

Gabeira, too, gets intimate moments that reveal much about his depth of character, especially when he clashes with the group's military leader (Matheus Nachtergaele), who feels Gabeira is just a middle-class kid not strong enough to die or kill for his cause or his compatriots.

Add to this Barreto's visual style -- a study in sunlight and shadows that captures both the texture of the tropics and the ominous pall of life under a repressive dictatorship -- and you have a sure-fire formula for success.

Four Days in September is a film as triumphant as the event which inspired it. A suspenseful thriller that makes you wish that somehow both sides could emerge victorious, it stands as cinematic proof that a film about violence doesn't have to be violent, that a film about torture doesn't have to torture its viewers to make its point.

It's the story of four days that lasted a lifetime. It'll stay with you for a lifetime, too.