Mission Impossible III is rated PG-13 for "intense sequences of frenetic violence and menace." That is pretty much all there is to this movie. It has all the meaning of a roller coaster at a theme park. While you are in your seat, the experience is sort of exciting and fun. But once those few thrilling moments are over, you come away with nothing to show for it.
The episodes of plot are mainly moments of rest that connect the explosions, gun battles, helicopter duels, people crashing through windows, and cars overturning on the highway and bursting into flames. To the movie's credit, some of these scenes of frenetic violence are well-done, especially when the hero jumps off buildings and when he tries to pick up a doomsday cylinder as it rolls through heavy traffic.
Ethan Hunt, played by Tom Cruise, decides to quit the impossible mission business to get married to a nice, wholesome nurse played by Michelle Monaghan (who constantly reminds us of Mr. Cruise's real-life crush, Katie Holmes). But an evil arms dealer, played by Philip Seymour Hoffman, kidnaps her, in an effort to get Ethan to turn over that doomsday cylinder. So Ethan has to rescue her. That's the plot.
The cylinder contains something so destructive it is called the "anti-God." And the government wants it given to a Middle East dictator to justify an invasion, so we have Hollywood's requisite anti-war statement. That's it.
We do, though, get a striking lesson in acting. The last time we saw Mr. Hoffman, he was earning an Oscar for his depiction of the effete, lisping Truman Capote. Now he plays the polar opposite: a big, strong, deep-voiced villain. Good, professional actors can utterly hide themselves in their different roles. But, like most mere movie stars, Tom Cruise, in all of his movies, always depicts the same character; namely, Tom Cruise.