Starring: Arnold Schwarzenegger, Nick Stahl, Kristanna Loken

Who would have thought that a movie with so much heavy metal would defy gravity?

That's not to say that Terminator 3: Rise of the Machines doesn't succeed as an action movie, or as a sequel. It has enough wanton destruction to satiate any person's desire for damage. It moves along briskly (perhaps too briskly), has a sense of humor, and even a more somber side that surprises near the end.

But what it does lack is gravity; some sense of realistic consequence. So if the question becomes, "Is it a worthy successor to the series?" the answer becomes a little murkier. It's unfair because director Jonathan Mostow, who did the serviceable U-571 and the overlooked thriller Breakdown, has to compete with one of the best storytellers in cinema, James Cameron, the director and writer of the first two installments. The screenplay here, credited to John D. Bracato and Michael Ferris, has several nice swerves as the film barrels along on its collision-course ending, but it lacks the common sense inherent in Cameron's work.

An example: Early on, veterinarian Kate Brewster (Claire Danes) goes to the animal clinic where she works only to have a disheveled, drugged John Connor (Nick Stahl) pull a gun on her. He's just broken in to her lab and taken some medication to enable him to either endure the pain of a motorcycle accident or perform minor surgery on himself as a result of same. Brewster overpowers him and locks him in an animal cage. At that moment, a customer comes in with a sick cat. Does our thinking heroine Kate say to the customer, "Hey, something weird just happened and a guy broke in here and I think he's high, and he may be dangerous. He's locked up, but please, call the police?" No. In James Cameron's treatment she would have because it would have made sense. We find out later that Brewster immediately recognized Connor from a junior high make-out party ten years earlier; he was the first guy she kissed. The day after the party Connor's stepparents were found dead (which occurred in Terminator 2: Judgment Day), he was on the lam, and she hasn't seen him since. But no, Kate shuffles the customer off so she can get back to a kid she kissed a decade ago to see if she can jog his memory. Connor then has the opportunity to assure her that, though he doesn't remember her, he didn't really didn't have anything to do with the deaths of his stepparents. Really.

Shortly after that, Kate Brewster is attacked by the T-X (Kristanna Loken), a new modification of the Terminator line. The Terminators are robotic assassins from the future who have a human appearance. In the future, a war between man and machine is ended by the heroic John Connor, who leads the humans in a successful coup against the dominant machines. The machines, rightly miffed, keep sending back new Terminator modifications in an attempt to kill Connor before he becomes a somebody. In this film, the T-X has been sent back to kill Connor's lieutenants--since they can't get a bead on Connor himself--including Kate Brewster.

But Kate isn't allowed the sense of numbed shock, of disbelief, even a "What the hell was that back there?" reaction. In defiance of all survival instincts, Kate continues to struggle against the two guys who have abducted her (Connor and the Terminator, played by Arnold Schwarzenegger) after the attack, even as they get her away from the nasty blonde who kills people and rips car doors off.

Meanwhile, Kate's father, General Robert Brewster (David Andrews), is facing a virus that appears to be infecting all civilian computers and slowly branching into governmental systems. He's advised that the only way to kill the virus is to give control of the network over to Skynet, the sophisticated new uber-program. Skynet, as all Terminator fans know, is the self-aware system that begins the war of man against machines. John Connor figures much of this out and it's a race to stop the initiation of Skynet and the judgment day so narrowly avoided last time.

Of course, the linchpin of this whole film is the return of the original Terminator, and Arnold Schwarzenegger doesn't disappoint. The fact that the machines didn't break the mold and that there were at least three versions of this model does call in to question just how hard it was to spot those early model Terminators in the future--"Hey, look, another Arnold Schwarzenegger is trying to infiltrate our rebel lair"--but maybe that's why the machines made the upgrades. Schwarzenegger looks unbelievably good for a man of 55 who has undergone heart surgery. In fact, he looks a little too good. Did the filmmakers, with his consent, graft his head on to his old body?

Whether they did or not, Mostow and company have great fun with the Terminator character. He's essentially comic relief in this film, which is a bit of shame, but Schwarzenegger fulfills his part with complete aplomb. Loken, on the other hand, isn't given much more to do than swivel her head and look icy. Frankly, the T-X, save a wicked right hand, isn't much of an upgrade from the T-1000 from T2 at all. She even sports an skeletal frame, which the T-1000 gladly did without.

She still gives our heroes trouble, however. An initial sequence, which features a heavy-duty crane, driven by the T-X, barreling through the streets of L.A., is undeniably impressive (ludicrous, but impressive). Unlike T2 however, there's nowhere else for the film to go after the sequence is over. T3 shoots its wad so early it spends the rest of the film trying to work up the same excitement. Consequently the film is rushed, never really pausing in its breathless race to achieve something of equal heft before the end credits.

It's done a lot to wear itself out, and when it's all said and done, T3 seems to be the one panting, not us.