A caravan of stretch limousines and black SUVs is rolling into Westwood for tonight's premiere. Hundreds of fans press up against the barricades, screaming and holding up camera phones, hoping to catch a glimpse of the biggest stars in the world. No, not the strange mix of guest celebrities in attendance — not Busta Rhymes, Helen Mirren, Brian Austin Green, Lance Bass, or the guy who played Pedro in Napoleon Dynamite. Not even the cast members of the movie itself: Shia LaBeouf, Josh Duhamel, Tyrese Gibson, Jon Voight. Those are all fine, talented, charming folks. But what the fans would really love, what would really blow their minds, would be if a few of those limos and Escalades lined up at the end of the red carpet suddenly morphed into 30-foot-tall mechanical beings, leaped into the air in heroic poses — laser cannons at the ready — and announced they'd arrived to do battle with the forces of evil and save the human race from annihilation. Flesh-and-blood stars are great, but tonight the people want robots.

After years out of the limelight, the Transformers are blasting away again. To nearly every boy (and a surprising number of girls) who came of age in the Reagan era, the valiant Autobots and villainous Decepticons — shape-shifting superbeings from outer space, able to turn into cars, trucks, planes, and pretty much any other vehicle except possibly a rickshaw or a unicycle — were among the most beloved childhood toys, figuring prominently from the mid-'80s to the early '90s in thousands of comic books, cartoons, and elementary-schoolers' notebook doodles. Now, like the Police, Eddie Murphy, and other '80s icons before them, they're back and walking tall.

Directed by Michael Bay and executive-produced by Steven Spielberg, Transformers tells the story of a suburban teen named Sam (LaBeouf), who discovers that the junky Camaro he bought for $4,000 is actually an alien robot — a nice one, named Bumblebee. After the U.S. military is attacked by other alien robots (not-nice ones with names like Blackout and Skorponok), Sam finds himself at the center of a battle between the Autobots, led by Optimus Prime, and the Decepticons, led by Megatron. This being a big, fun summer popcorn movie, the battle could end in the enslavement of humankind. ''All my friends, they're normal Joes, they were like, 'What the f--- are you doing that movie for? That sounds stupid,''' Bay says. ''[But] it's like the kid comes out in you when you see this movie. It's just fun.''

Still, as the Transformers' theme song goes — all together now, kids — there's more than meets the eye. For Bay, whose fast-paced, glossy, testosterone-drenched actioners include Bad Boys, The Rock, and Armageddon, Transformers is a chance to rebound from 2005's The Island. For Paramount and DreamWorks, which are bankrolling the $150 million production, it's a shot at a potentially massive new franchise. For LaBeouf, it's a critical stepping-stone toward his upcoming starring role in Indiana Jones 4. To the film industry, Transformers represents not just another big, shiny, effects-driven blockbuster but the prime (as in Optimus) example of extreme product placement. Like a Transformer, the film does double duty: as both a piece of entertainment and the world's most expensive toy commercial. How successful that fusion proves will likely provide a harbinger for the future.

As they stroll the red carpet, the film's flesh-and-blood stars seem perfectly aware of their place in the pecking order. Even a celebrated Oscar winner like Voight, who plays the flinty U.S. Secretary of Defense, happily accepts being just a piece in the larger game. ''The robots are cool,'' he says. ''I like watching the robots better than me.''

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