Tom Selleck finds a niche for his dimpled affability in "Runaway," but the real stars of this sci-fi thriller are the machines. Garrulous robots perform household chores or pluck slugs from plants, and the villain uses miniature cruise missiles and mechanical spiders with chattering limbs to do his bidding. It's a fun, negligible movie -- more "throwaway" than "Runaway" -- marred only by writer/director Michael Crichton's characteristic sourness.

Selleck plays Jack Ramsay, a cop who specializes in "runaways," the name this futuristic culture has given to robots gone haywire. "Relationships don't work right, people don't work right," Ramsay opines philosophically. "Why should machines be perfect?" It doesn't help things, of course, when human beings like the evil Luther (Gene Simmons) invent chips that actually make robots run amok.

Accompanied by his partner, Karen Thompson (Cynthia Rhodes), Ramsay takes off after Luther, but he's got a handicap -- he's afraid of heights. If this sounds familiar, that's because it is -- Crichton has stolen the setup, as well as his style of bringing the phobia to film, from Hitchcock's "Vertigo." But where a movie like "The Terminator" performed its artistic thieveries with an adolescent's glee, "Runaway's" plagiarism has the cynical dreariness of white-collar crime.

Staring up through his eyebrows, his pendulous lower lip drooping like a festooned drape, the saturnine Simmons sends up the dastard to sometimes hilarious effect; as his girlfriend, the vivacious Kirstie Alley presents the dark side of The Cosmopolitan Woman. What's interesting about "Runaway" is the way these performances bring class consciousness to sci-fi villainy -- the well-tanned Simmons dresses like a smoothie at Regine's and talks with an overeducated lisp, and Alley, whose streamlined curves are elegantly draped, brings a bitchiness to her role that bespeaks years of overindulgence.

Selleck and Rhodes, by contrast, eat pasta at home and generally knock around like a suburban couple looking lost at the mall on a Saturday afternoon. Despite his matinee-idol good looks, Selleck's appeal lies in his boy-next-door good-naturedness -- he may be afraid of heights, but he's more afraid of hurting somebody's feelings. Rambling around gawkily on her long legs, Rhodes, with her soft, plush cheekbones, is as ingratiatingly awkward as a foal.

You like these people, but Crichton doesn't -- he seems more interested in the machines he's created, which he shoots with shiny high-tech zing and zong. The fun of the movie comes from the way Crichton joshes his own material; it's full of hooters poking fun at sci-fi's self-seriousness. But Crichton's a director as cynical and manipulative as his villains. Everything turns to formula here -- the fun of the jokes curdles, since, for Crichton, it's just another way to push the audience's buttons.

"Runaway," now playing at area theaters, is rated PG-13 for violence.