"Blade Runner," a voluptuous vision of the future imagined by the late sci-fi novelist Philip K. Dick, pursues the existential basics: life, death, and whether, as star Harrison Ford put it, "you can actually profit from a love affair with your toaster."

This opulent odyssey, directed by post- Modernist Ridley Scott, is set in 2020 Los Angeles, now so filthy that the sun's a dull smear. Ethnics and eccentrics pack the district called Little Toyko, with Hare Krishnas brushing saffron robes with punks, Hassidic Jews and coolies. It is a crowded bazaar, clogged with garbage and bicyclists. Neon lights flicker through the continuing rain in an exotic megalopolis conceived by Scott, Douglas Trumbull and company.

Against a backdrop of floating, bloated video billboards and 400-story skyscapers is set a detective tale as familiar as "Farewell, My Lovely." Harrison Ford plays retired detective Rick Deckard, who delivers his lines deadpan and hardboiled: "Sushi" -- pause -- "That's what my wife called me." He's a cold fish, all right, but he meets a dame so smooth and shining that he reluctantly falls in love.

The dame's real special. She's Sean Young, co-starring as Rachael, a Nexus 6 Replicant, or a "skin job" in street lingo. She's "more human than human" promises the Tyrell Corp., which genetically engineers Replicants for space colonization -- except Rachael, who was made solely for the chief flesh peddler, Tyrell himself.

Rachael, unlike her kind, has been given a memory. She doesn't know she's not Homo sapiens till she faces the Voight-Kampff machine, a sophisticated lie detector. The test is given by a blade runner, the guy you call in to "retire" the renegades. That's street talk for exterminate them.

Rick, an out-of-work blade runner, is about to load a chopstick with raw tuna when he's forced back to active duty by the police. Four offworld Reps have shipped back to Earth and are looking for their maker, the guy who gave them emotions, the capacity to love, and only four years to enjoy the feeling. They want more time for toasting. And who can blame them?

What a quartet they are, too, with handsome Hollander Rutger Hauer, wonderfully cast as the white-haired psychotic Roy Batty, the vile but genetically pure leader of these violent superior beings. Roy, designated a warrior, loves the deadly Barbie-doll Pris (Daryl Hannah). Their co-conspirators are Joanna Cassidy, a combat-ready exotic dancer, fake as her synthetic snake; and Brion James as her lover Leon, a lumpy, big- fisted sidekick for Roy.

There's some gruesome dueling between Rick and the Replicants, but the violence becomes artful under Scott's direction. When Rick "retires" the dancer Zhora, she is wearing a kinky black bikini under a clear vinyl raincoat. She falls through window displays, the streaming blood candy-striping her coat, the glass shards and tearing skin forming a pattern of terrible beauty.

Rick, like all old-fashioned gumshoes, is a fatalist, but with a conscience that stirs no matter how much booze he swills. Worse for the blade runner, he knows he's beginning to think of life as life and "retirement" as murder. And then there's this Rachael business. He unmasks her, proves her mother's a big petri dish and not the smiling woman in her treasured snapshot. (The still photograph for an instant becomes a moving frame.) Later, she saves Rick's life by shooting Leon, and though it's his duty to kill her, he owes her his life.

She comes to his apartment as an ice queen, her mouth harsh and red, her hair upswept and stiff, shoulders squared. But he has that rakish way so she loosens her hair while he sleeps. Her hesitant piano-playing becomes part of the understated Vangelis score, a mixture of Moog indigo and mood synthesizer. It is mellow in the smoky room. The camera relaxes, too, when it looks at Rachael now. She and the other actors are treated tenderly, with as much regard as the stupefying effects. Or more.

Harrison Ford, humbled to some degree by the brutal, moving performace of Hauer, is his charming self, plucky like Han Solo, but with a glum twist. In his love scene with Young, well, he's rough and steamy. Few folks have ever come on with their toaster in quite so flashy a way. Clark Gable maybe, but certainly no one else.

What consenting adults do with their appliances in the year 2020 may not sound like much to concern yourself with, but much of "Blade Runner's" audience will still be alive and cooking. BLADE RUNNER -- At AMC Carrollton, Hampton Mall, K-B Cerberus, K-B Congressional, K-B Silver, NTI Arlington, NTI State, NTI Tysons Center, Showcase Beacon Mall, Showcase Bradlick, Showcase Mercado and Tenley Circle.