OK, now I get it. As one of the three or four critics who didn't particularly dig the critically and commercially successful "The Bourne Supremacy" when it came out (although I did love "The Bourne Identity"), I wondered if that was going to be the case with the newest Jason Bourne installment, "The Bourne Ultimatum." Would I again sit in the theater miffed about what exactly I was watching, how nothing makes sense and how could that man-pretty Matt Damon kick anybody's behind with just a rolled-up magazine?

However, I'm pleased to report that "Ultimatum" sits quite well with me. Of course, since this has been a summer that has given moviegoers nothing but dismal, disappointing "blockbusters," any studio movie that's remotely interesting seems marvelous in comparison. Still, "Ultimatum" is an invigorating pick-me-up after consuming nothing but putrid concoctions.

Damon reprises his role as Bourne, the assassin who knows too much -- yet can't seem to remember any of it. He's back on his globe-trotting mission to 1) find out who he is and where he came from, and 2) avenge the death of his girlfriend, who took a sniper bullet in "Supremacy." He travels from London to Madrid to Tangier to back to the old U.S. of A., all while dodging the various "assets" who have been dispatched by Noah Vosen (David Strathairn), the head of an umbrella black-ops program, to eliminate Bourne before he gets too close to the truth.

Although, on paper, the whole thing sounds more like a video game than a movie, "Ultimatum" is an engrossing espionage adventure. Director Paul Greengrass stages some of the action scenes like well-choreographed dance routines, with Damon, gliding through the movie like a cross between Baryshnikov and MacGyver, as his most experienced hoofer.

From a visual standpoint, "Ultimatum" is no different from "Supremacy." Greengrass, "Supremacy" director (and recent Oscar nominee), returns to give us that herky-jerky, way-too-up-close-and-personal cinematography that riveted some and nauseated others. And, just as in "Supremacy," the story barely resembles the Robert Ludlum novel it's based on.

And still, "Ultimatum" gets you in its hooks not just from its full-throttle action scenes, but in its suspenseful, engulfing plot. "Ultimatum" continues the theme started in "Supremacy" of making its hero take responsibility for his actions. Although Greengrass and the screenwriters give us a cool, quick-witted action hero who can jump through buildings, they never let him off the hook morally. No matter how hard he runs, he's never going to escape his demons.

"Ultimatum" features one of the best top-notch casts you'll see this summer. Joan Allen returns in her "Supremacy" role as a sympathetic CIA investigator, with Scott Glenn and the esteemed Albert Finney stepping in as shadowy government figures. Greengrass even manages to squeeze talented international actors Paddy Considine, Edgar Ramirez and Daniel Bruhl into the mix. But what's the most surprising is how this movie finally finds a use for Julia Stiles. Long considered the sore thumb of the whole series, Stiles actually becomes a vital component in this movie, as her callow CIA operative aids Bourne in his journey and becomes a target herself.

All this adds up to a superior popcorn-movie experience I wouldn't mind seeing again. After three months of big-budget clunkers, this is one "Ultimatum" everyone should choose to accept.