Columbia Pictures is billing "21" as an action/adventure film. That's cheeky, considering the lead characters are college-age blackjack card counters who do not carry weapons, or deal with terrorists, or leave the casino for very long, unless they're back on campus at the Massachusetts Institute of Technology, that hotbed of action/adventurism.

In real life the MIT gang of card-counting wizards who raked in millions was spearheaded by a kid named Jeff Ma. Can you guess what's different about the Ma character now that he has become the protagonist in a major studio release? If you guessed "he's taller," you're incorrect. The correct answer is "he's whiter." He's now as pasty white as they come. And not just American pasty white; No, for "21," they went with Jim Sturgess, who hails from England, where "pasty" knows no bounds.

Sturgess, recently in "Across the Universe," is good in the film, actually. So is Kevin Spacey, who optioned the nonfiction best-seller "Bringing Down the House" and who plays the Mephistophelean MIT math professor who bankrolls his young phenoms. So is Laurence Fishburne, as an old-school Vegas security expert who smells rats when the phenoms start winning big.

Everything else, not so good. "21" isn't pretentious, exactly, but it's damn close, and in trying to whip up a melodramatic morality tale the film becomes an increasingly flabby slog. Director Robert Luketic ("Monster-in-Law") is so determined to wow us with technique (digitized effects for simple things, like HUGE face cards floating through the air, or chips flying across green felt landscapes), he forgets about making the ensemble compelling, or mining the dramatic and comic possibilities of watching a group of kids barely old enough to drink legally responding to the PG-13 temptations of Vegas.

Sturgess' character is set up as a salt-of-the-earth working-class guy, ripe for corrupting. Nearing the end of his MIT studies, eyeing Harvard Medical School if he can pull in a scholarship, Ben's lured into the web of the underground card-counting Ocean's 11-ettes run by Professor Micky (Spacey, gliding through this assignment with his patented air of sideline amusement).

It's a rise-and-fall-and-rise-again tale. Ben, lured also by cryptically seductive teammate Kate Bosworth, can barely get his head around the jet-setting double life of Vegas lounge lizard by night, bleary-eyed MIT student by day. Soon he forgets Micky's principal rule: Don't play your hunches. Soon he gets sloppy at the tables and starts costing his boss lots of winnings. Soon Fishburne, who may be the only actor in Hollywood who can out-glide Kevin Spacey, starts making life difficult for the gang.

And while you may stick with the film - it's a slick time-waster - you never believe it. It feels hoked-up and pumped-up and phony, despite its best performers. Those performers include Liza Lapira, who - nothing against Bosworth - is, well, a lot more interesting than Bosworth. (I suppose that is something against Bosworth.) Nobody expects a film version of any nonfiction story to stick to the facts. But "21" cannot make us care enough about Ben or his double life. There's scarcely enough rooting interest at work for a single one.