When an important Chinese government figure is nearly assassinated, Inspector Lee (Jackie Chan) desperately follows the clues to the heart of a criminal empire. Tagging along is Lee's pal Carter (Chris Tucker), who craves the excitement. The journey takes them to Paris, where Carter and Lee quickly find themselves in over their heads dealing with Triad complications (Hiroyuki Sanada), a mysterious nightclub performer (Noemie Lenior), and a bureaucrat (Max von Sydow) who wants this case put to bed quickly.

The quality of the "Rush Hour" films always depends on to the potency of the material. 2001's "Rush Hour 2" was a near-perfect realization of the formula, lurching through expansive set-pieces like a steamroller and exploiting the cultural friction between Tucker and Chan to comedy gold. It was a popcorn enterprise of the highest order, miles ahead of 1998's "Hour 1."

One can sense a certain sleepy quality about "Hour 3," as though the financial impetus of the series is starting to lean heavily on the imagination of the filmmakers. The new picture doesn't feature a particularly robust story, but director Brett Ratner is convinced it's his duty to sell the twisty turns of the lackluster script, as though the audience actually cares who did what to who and when. Buddy, we're all here for laughs and a couple of broken bodies.

When "Hour 3" slips back into familiar theme park stunt show theatrics, the results are thrilling. Criticize Ratner as a Hollywood brat, but the man can capture a scene of circus-like velocity unlike many of his generation. Hustling around the frame, spanking cities such as Los Angeles and Paris as Carter and Lee tear up the streets, "Hour 3" plays unswervingly to expectations, but they're deliciously frenzied expectations with dynamite results. Ratner stages his action beats big and broad (a Parisian taxi chase is a standout), yet the film never feels bloated like so many sequels this summer. "Hour 3" isn't so much trying to top itself as it is looking to recall why viewers took interest in the first place. There's a certain appeal in that.

To fend off franchise fatigue, Ratner has cast the film beautifully, throwing in an international collection of faces (including Yvan Attal, Roman Polanski, and Youki Kudoh) that help out Tucker and Chan when their traditional performances start to show unmistakable signs of rust.

Chris Tucker seems the most inert during the new "Hour." Certainly his smack-talkin', horndog creation of Carter is allowed plenty of room for jokes, and Tucker lands his share of the laughs (he's hard to resist when he quickdraws his wildest reactions); however, this is only Tucker's third film in a decade, and the last two were the earlier "Hour" installments. One can sense a lack of lubrication to Tucker's motor-mouth: the actor pushes far too hard to be hilarious when it used to be so effortless. Of course, there are gigantic laughs to be devoured in "Hour 3" (a brief episode of separation between Carter and Lee is the most inspired comedic concept of Ratner's career), but the stretch marks are starting to show in this round.

For the finale, the film explodes with an Eiffel Tower showdown, making the most of Chan's choreographed spasms, but finding itself with surprising little invention to bounce off of. This is not a question of familiarity, just fatigue. "Hour 3" closes the series on a pleasing note, and there's little disagreement from me about the way Ratner is simply flying through the motions. After all, these are fun motions. Still, it's time to close the book on this peculiar franchise, and "Rush Hour 3" is a satisfying spin around the punch-n-giggle track.