(CNN) -- It's not easy, being Bourne again. It means a lot of miles, a lot of challenges, and all for uncertain ends. And you never know what you'll have to explain: "My fight is not with you," Matt Damon's amnesiac rogue CIA agent, evading capture in Moscow, says to a local cop in Russian before beating a nonviolent retreat.
Matt Damon's Jason Bourne remains on the run in "The Bourne Ultimatum."
Thus begins "The Bourne Ultimatum," the series' third and final installment.
Despite a marked limp in this early running, Bourne remains on the run, globe-hopping to Paris, London, Madrid, Tangiers and finally home to New York.
He's also getting closer to connecting the dots and discovering his true identity. But it's not just the "who" that drives him, it's also the "why": why was he brainwashed into an implacable, impervious -- and it seems, just about impregnable -- killing machine?
The Bourne series gets a lot of credit for a supposedly more hard-nosed, contemporary take on espionage than other spy movies we could mention. This is largely a function of style. Bourne travels light and adopts a pragmatic, hands-on approach to problem solving. He has no truck with the CGI that's got the better of "Die Hard" cop John McClane.
But when the bullets fly he's as Teflon as the next superagent. One minute he's floored by a bomb blast, the next he's sprinting across rooftops like he's trying out for a triathlon. He's one-man surge. Watch an audio slide show with 'Bourne' soundtrack composer John Powell
This being a Paul Greengrass movie -- he directed "The Bourne Supremacy" and "United 93" -- the shock absorbers are off, the framing is epileptic and it's a rare shot that lasts more than a millisecond. The effect is purposely disorienting, but even in the midst of this breathless visual bombardment Greengrass, his cinematographer Oliver Wood and editor Christopher Rouse have a knack for homing in on the vital dynamic element in the frame, even if we're only able to process the information a beat or two later, when that blurry gun, or book, or voice recorder comes in to play.
Indeed, the action pounds so thick and fast, it's a relief when hard-working composer John Powell grants us a brief reprieve for a brutal hand-to-hand scrap scored only to thumps, bumps and grunts.
Still, much to Greengrass and Co.'s credit, they want to get to the "why," too. It takes awhile: that's not a question CIA headquarters is ready to address, and certainly not in public. CIA deputy director Noah Vosen (David Strathairn) is aghast when the agency picks up a British journalist's reference to the top-secret codename "Blackbriar" in a cell phone conversation with his editor. (Forget the Patriot Act; these guys are eavesdropping across the Atlantic now.)
In the first of the film's dizzyingly orchestrated cat-and-mouse sequences, Bourne steals the reporter out from under a thousand virtual Agency eyes and ears in London's Waterloo Station. (Tip for the terrorists: to avoid detection, when all else fails, tie your shoelaces.) The hack doesn't make it, but Bourne is nothing if not elusive, and it's on to the next stage in his whirlwind European tour. Along the way, he has a suspiciously serendipitous encounter with old acquaintance Nicky Parsons (Julia Stiles), before executing another adept variation on an escapist theme.
Bourne -- or whatever his name really is -- is such a resourceful and reckless agent of chaos, we thrill to him despite the fact that he's officially a non-entity. Matt Damon makes enough of his scarce, terse exchanges with Nicky and Pamela Landy (Joan Allen) to suggest remorse spurs him more than revenge.
Landy in particular comes to figure as a mother-confessor. She's the only one who understands Bourne's true nature: blowback.
Which turns "The Bourne Ultimatum" into a thinking-man's action film. Reflecting a growing apprehension that counterintelligence agencies have overstepped legal and ethical boundaries, "The Bourne Ultimatum" smartly affects kick-ass with a conscience by implying we've become our own worst enemy. Who knew guilt could be such a trip?