WILL SMITH just ran into something unusual for him lately: a summer movie hit.

Oh, it's a hit. You know it. And that's good news for us, the willing minions of the military-industrial-complex of Sonys, Warners and other Big Brothers Inc. of our collective entertainment. "I, Robot," which intercuts live action and computer-generated imagery with breathtaking seamlessness (can we still use tailoring terms for these things?), is fabulous mental escape. It's fun and playful, rather than dark and foreboding. And there doesn't seem to be an original cyber-bone in the movie's body. But it's put together in a fabulous package.

There's one crucial reason behind the movie's success. Drumroll, please: It's a great story by Akiva Goldsman and Jeff Vintar. This futuristic flickorama, supposedly an amalgam of Vintar's original script ("Hardwired") and Isaac Asimov's "I, Robot" collection of short stories, flows nicely. The wonderful robot effects, Smith's likable personality, Alex ("The Crow") Proyas's atmospheric direction and so on? They're top-notch, sure. But it's the story that makes them work, makes it all happen.

Smith plays Del Spooner or, more accurately, Will Smith. But that's all right. That's what people come for. Spooner has never liked robots, which have become ubiquitous in 2035. Chicago, and the rest of the world, teems with them. As created by the benevolent Dr. Alfred Lanning (James Cromwell), the NS-5 robots, which have positronic brains, are built to serve and protect humankind. They are almost human, with their hard-wire circuits designed to obey three simple laws. All of them have to do with safety for humans first and robots second. These robots would never, never, never do anything scary or harmful toward people.

Guess where this story is going.

Spooner suspects robot intrigue after the mysterious death of Dr. Lanning, who has fallen from a tall building. But suicide is the official conclusion by USR Corp., run by the cold, distant, corporately hissable Lawrence Robertson (Bruce Greenwood). And Spooner's cliched African American superior (who, yes, is feeling pressure from above) buys the story, too.

Spooner's hunch proves right when an NS-5 robot named Sonny, one of the seemingly faceless billions, attacks him and makes an attempt to escape. With the slow-moving help of Susan Calvin (Bridget Moynahan), a psychologist with an expertise in robots (or something), Spooner begins to uncover, well, what detectives always do in these films. Time is running out. The NS-5 series is scheduled to be employed in every home.

I think 21st-century humankind could have done without Spooner's cutesy grandmother (played by Adrian Ricard), her existence a clear attempt to reprise the successful family scenes in the "Spider-Man" films. And I would have loved to see one of the NS-5s deep-sixing Farber (Shia LaBoeuf), a completely irrelevant kid pal of Spooner's, who's only in the movie to make the teenagers in the audience feel appreciated.

Also, was it in Smith's ego contract to emphasize his body build and appear in a ridiculously contrived shower scene to thrill da ladies? Puhleez.

For the most part, this is thrilling fun. And if you remember it more than 23 minutes after you've seen it, you're missing the point. And speaking of remembering things, is it possible that the filmmakers have slipped in a few political jibes against the Bush administration? The villain at the center of all this makes comments about protection against the enemy and forcing society to suffer a little loss in liberty; and it seems that the good robots are sort of bluish, while the evil robots are, you guessed it, red. Well, it's a minor topic for the parking lot afterward. The bigger topic, really, is the sheer fun of all this.

I, ROBOT (PG-13, 114 minutes) -- Contains computer digital violence and maybe a mild flash of nudity. Area theaters.

As detective Del Spooner, Will Smith suspects robot intrigue on his hunt for a killer in the sci-fi action flick "I, Robot," set in 2035.