T-X, a female terminatrix, stalks John Connor in contemporary Los Angeles. The future rebel leader is protected by a familiar T-101 model, whose mission is to keep Connor alive on the day when the Skynet system is due to launch its first attack on humanity.
James Cameron is gone, and Jonathan Mostow (Breakdown) is ringmastering the stuntwork. Sarah Connor is dead, signalling Linda Hamilton's departure, and leaving Nick Stahl's jittery John Connor and Claire Danes as his bewildered, predestined wife to shoulder the human side of things.
Schwarzenegger's admission that the sleek, blonde T-X is far superior to his T-101 because he is "an obsolete model" has a certain extra-filmic poignancy given that the former box office champ has been on a slide since, well, Terminator 2: Judgment Day.
Also, the CGI that made the first Terminator sequel such a revelation a decade back can now be approximated by kids with home computers, suggesting this franchise might fall prey to its own nightmare vision and be rendered extinct through mushroom-growth technological progress. And yet, T3 does what it does with machine-like efficiency.
Cameron's films were ground-breaking melds of action, effects and time-trickery - signature films of the '80s and the '90s, the ruthlessness of the first softened by the reworking of Arnie's cyborg killing machine as a good-guy protector of children in the second.
T3 can't punch in that league, and sometimes verges on parody of its earlier instalments - Schwarzenegger struts nude into a redneck bar to be mistaken for a stripper by a raucous hen night, then cops his familiar threads from a gay dancer (whose star-spangled shades are ditched in favour of something cooler.
Since audiences loved Arnie's gag lines, everything he says here has some double meaning or back-reference to spur a cheap laugh. Even the fearsome supermodel-look T-X inflates her breasts to impress a traffic cop before cutting loose with a succession of creepily flexible moves and morphs all the more effective for not being showstoppers like the liquid metal gags from T2.
Sarah Connor didn't prevent Judgment Day at the end of T2, she just put it off. Those following the convoluted timelines of the series - as mutable pasts, presents and futures are created and taken back between loud action scenes - will probably give up after five minutes and go with the ride.
Stahl, using junkie mannerisms that might be construed as a nasty joke at Edward Furlong's expense, and Danes, who essentially has the Sarah role from the first film, are an appealing anchor for the thin story, which is really an excuse for a succession of chases.
The T-X has a new gimmick - remote-controlling other machines - so there's a bravura bit as she commandeers a fleet of emergency vehicles to pursue a fleeing veterinarian ambulance while the T-101 doggedly rides to the rescue in a fire-truck. Later, at a military HQ, the first-generation clunky ancestors of the terminators are wheeled on to show the beginnings of the man-machine war that rages in the films' future.
For 90 minutes, all the intellect and most of the emotions of the earlier films are put on hold in favour of gunfire and excitement. But the last scenes spring a genuinely surprising, affecting finish that recalls the haunting mix of pessimism and determination at the end of The Terminator and - of course - leaves things opens for another re-run.
A sleek, satisfying return to the series supercharged B-picture roots, this is certainly not the disaster Cameron fans feared. In franchise terms this is like a lesser Bond but its still a great way to kill (for) two hours.