The opening scene of "Duets" is a gem. '80s yuppie-rocker Huey Lewis walks into a karaoke bar sporting shop-class glasses and a thrift shop polyester suit. Turning the doofus volume up to 10, he starts popping off about how this singing-along thing doesn't look so tough, and before long he's bet the joint's champion amateur crooner a fat wad of cash that he can win the evening's singing competition.

Way before the hayseed patrons catch on, you've realized Huey is a fly-by-night karaoke hustler! What a great comic concept. As he belts out a Joe Cocker tune and takes off with the money, you'll even be reminded of how annoyingly catchy Huey Lewis and the News' cheesy pop anthems were way back when.

But then he goes home with some bar tramp at the end of the night, and the movie's tone goes into a steep tailspin of narrative miscalculations and cinematic ineptitude that ends in a crash with no survivors. Instantly you can't stand this Lewis' character. He's exposed as a sorry, irresponsible slimebag. To make matters worse, when he's not singing, Lewis' acting is so wooden that if you were there when he fell in the forest, you still wouldn't hear anything.

Soon it's revealed that he has a daughter he's never met, played by Gwyneth Paltrow with such whiney ditziness that even she -- Miss Hollywood Sunshine -- is almost unwatchable. In a contrived, only-in-the-movies bonding ritual, they hit the road together, singing here and there on their way to some big karaoke championship in Omaha.

Directed by Gwynnie's pop, Bruce Paltrow, "Duets" preaches karaoke -- that inexplicably fringe-popular, sustained fad of average Joes and Janes jumping on stage (usually after one too many cocktails) to sing off-key over prerecorded music -- as an all-purpose cure for the human condition.

Not only does karaoke bring reluctant father and wounded-child daughter together, but apparently is an elixir for bad breakups, low self-esteem and mid-life crises as well.

An ensemble melodrama-comedy that tries to have it both ways and fails, the movie features two other stories that fumble all their feelings so badly that every character becomes quickly and pathetically grating.

Entertaining character actor Paul Giamatti ("Private Parts," "The Negotiator," "Man on the Moon," "Big Momma's House") plays a miserable suburbanite traveling salesman, ignored by wife and kids, who gets his ear pierced and hits the road after discovering the joys of belting out show tunes in random roadhouses. He picks up a hitchhiking escaped con (Andre Braugher) who becomes his singing partner and his conscience in a storyline ripe with comic potential (Giamatti wants to rob gas stations and convenience stores) but played as drippy, dopey melodrama.

Scott Speedman (who stepped into Brad Pitt's role after he and Paltrow split just before filming began) plays a naive, spiritually lost cab driver coming off a bad breakup. Drowning his sorrows at a karaoke watering hole, he agrees to drive brassy Maria Bello ("Coyote Ugly") cross-country while she sings for her supper and degrades herself performing sex acts for free hotel suites night after night, all the while insisting loudly she's perfectly content with her lifestyle.

The trio of road trip tales all converge for the Big Competition finale, where trite, ham-fisted life lessons are laid on thick.

"Duets" has a plot with potential. The karaoke hustler idea was a good one, but director Paltrow fails to follow through. Lewis only attempts one more swindle and he botches it in a way that isn't even entertaining to watch.

Had Giamatti and Braugher busted out into a comedic crime spree (I envisioned "Bonnie and Clyde" meets "Cannonball Run"), knocking off Sip 'n' Go shops between compulsive singing pit-stops, that storyline might have been salvaged instead of becoming an absurdly heavy-handed redemption parable.

The taxi driver/strumpet story was beyond hope from the word go, even though Bello's trademark tough-cookie-cutie characteristics carry it a certain distance.

Long before "Duets" turns irretrievably in an even more sour and ugly direction (let's just say it involves a gun), the film becomes an endurance test of tedious -- even painful -- labored dialogue and flat, counterfeit emotions. (The signing, however -- done by the actors themselves -- isn't half bad.)

Gwyneth Paltrow must love her father a lot to be party to a movie this boorish. As for the others, I can only imagine they needed the work.