Has there ever been a movie more ecstatically action-packed than "The Bourne Ultimatum"? I can't think of one. Even a supercharged rampager like "District B13" had occasional moments of respite. There's no such wussery here. The picture kicks off in mid-chase, and it's a good 45 minutes before two of the characters finally take five (or maybe three) to catch their breath. Director Paul Greengrass, faced with the formidable task of one-upping his previous entry in the series, the already-frenetic "Bourne Supremacy," has pulled out what few stops remained and plunged headlong into pure kinetic delirium. It's a wildly exciting film; an action classic. But it also teeters right on the edge of what might be called the James Bond Abyss. More on that in a moment.

This time out, the amnesiac CIA hit man Jason Bourne (Matt Damon), still in search of his true identity, confronts a high-level Agency conspiracy even more serpentine than the Treadstone operation he helped shut down in the last movie. This one's a deep-cover assassination bureau called Blackbriar, headed up by the snotty spymaster Noah Vosen (David Strathairn). Vosen is alarmed to learn that a British journalist (Paddy Considine) has acquired secret documents that lay bare the Bourne-Treadstone story -- and will inevitably shine an unwanted light on the shadowy Blackbriar, too. To his further annoyance, Vosen must also butt heads with Pamela Landy (Joan Allen), the Agency's deputy director, who's still on Bourne's trail, and slowly coming to realize that he's not one of the bad guys -- the bad guys are actually all around her. Also on hand from the last film is Nicky Parsons (Julia Stiles), Bourne's Treadstone handler, whose roots in this tale are deeper than previously suspected. And making his debut is a sinister neurosurgeon named Hirsch (Albert Finney), who's on hand to shovel in some alarming backstory.

The movie is a globe-spinning procession of virtuoso action sequences: a tumultuous pursuit through London's Waterloo station; a mad bolt through a Moroccan souk; furious one-on-one smack-downs in Moscow and Madrid; and of course a spectacular array of window-leaps, car-wreckery, and scooter-borne wall-climbs. These masterfully constructed set pieces aren't simply lined up and ignited; they build thrillingly in both complexity and intensity (and are all the more impressive for being performed, once again, by real people, not digital avatars). The director's technical facility is breathtaking; his arsenal of indy-style whip-blur, semi-blocked shots and machine-gun editing draws us into the action with an intimacy that remains unique among big-budget blockbusters. (His knowing touch with espionage material is also unusual, possibly informed by his research for "Spycatcher," the scandalous 1987 British Intelligence exposé he co-wrote with former MI5 operative Peter Wright.)

Matt Damon, who has by now attained an Olympian level of physical conditioning, continues to find pockets of vestigial warmth in Jason Bourne; no doubt he could continue peeling back the character's emotional layers for another five years and still keep us interested (see [article id="1566239"]"Matt Damon: The Unlikely Action Hero"[/article]). In fact, he well might -- a sequel is matter-of-factly prefigured at the end of this picture. (Author Robert Ludlum only wrote three Bourne novels; but after his death in 2001, his estate granted permission to an equally prolific thriller specialist, Eric Van Lustbader, to write two more.) If Greengrass were to stay onboard, along with his superb editor, Christopher Rouse, and his chief writer, Tony Gilroy, the Bourne saga might possibly become a franchise of rare high quality.

That's not how things generally work with franchises, though. The creators inevitably drift away, and journeymen rush in to fill the void, with a resulting descent into uninteresting preposterousness where once there was style and excitement. In the James Bond series, for example, the tipping point may have come as early on as the 1967 "You Only Live Twice," in which the already-fanciful superspy action floated off into outer space. The Bond movies never quite recovered from this.

The Bourne films are nowhere near that point, of course. But already certain of their elements are becoming familiar: the world-girdling computer wizardry ("Give me eyes at Waterloo!" Vosen yells to his laptop-tapping minions); the intricately-choreographed mano-a-mano mayhem; the scene in which Pam is murmuring to Bourne on her cell phone, unaware that he's observing her from just a rooftop away. There's even a reprise of the haircutting and -dyeing interlude in the first film (leaving open the hopefully remote possibility of a Supergirl-style spinoff series in the future).

"The Bourne Ultimatum" might have brought this saga to a classy and gratifying conclusion. It's hard to imagine how any further sequel could improve upon it. The series is going to keep going, though -- it's now too profitable to turn loose. We'll keep watching, of course, and hope for the best. Don't bet on it, though.

Check out everything we've got on "The Bourne Ultimatum."

Visit [article id="1488131"]Movies on MTV.com[/article] for more from Hollywood, including news, reviews, interviews and more.

For breaking news, celebrity columns, humor and more -- updated around the clock -- visit MTVMoviesBlog.com.

Want trailers? Visit the Trailer Park for the newest, scariest and funniest coming attractions anywhere.