At the beginning of “21,” naïve Ben Campbell (played by Jim Sturgess) asks an admissions director at Harvard Medical School what he has to do to get the prestigious Roosevelt scholarship.

“You have to dazzle,” the older man replies, no doubt in an attempt to set the audience up for the series of glittery adventures through Las Vegas Campbell is about to engage.

Unfortunately, however, the film fails to dazzle on any level, faltering through its repetitiveness, clichéd romance and dismal lack of spunk.

For those unfamiliar with the plot of “21” or the book it is loosely based off of, “Bringing Down the House: The Inside Story of Six M.I.T. Students Who Took Vegas for Millions,” the movie follows a group of whiz kid students who, led by their dubious math professor Micky Rosa (Kevin Spacey), make money in Las Vegas by counting cards at blackjack. The students use coded language and hand signals to communicate with each other, and, while card counting is legal, change their identities with fake IDs and disguises to avoid being caught by the pushy casino staff.

Although “21” is ultimately based on a true story, the movie never really feels believable because of multiple inexplicable puzzles in the story’s plot (presumably added for dramatic effect). The hand signals, at least as performed, seem awkward and obvious (crossing your hands behind your back?), and Campbell stores all of his money in a hole in his ceiling in wads of bills rather than placing any of it in a bank.

The most disappointing thing about “21” is that it could have been interesting. The premise of M.I.T. students (who are inherently nerdy and quirky) flying back and forth between Boston and Vegas, is one filled with potential for both comedy and an inspiringly scrappy upset of social expectations. Instead, miscasting and unoriginal plot decisions make the movie dull and wearisome.

Sturgess’ Campbell is breathy and over-serious, and though “21” is based on the premise that the character undergoes a coming-of-age type transformation, Sturgess’ acting certainly doesn’t show it. “I’m not the same man I was back in Boston,” he tells Jill Taylor (Kate Bosworth), his girlfriend and fellow card counter, leaving the audience wondering when Campbell went through his stale and unimpressive metamorphosis.

Bosworth, similarly, is almost hopelessly bland. This is emphasized by the fact that she maintains her vapid demeanor while constantly changing costumes and shopping at expensive stores with her questionable earnings, exposing the gap between Bosworth’s acting skills and her scripted character.

Laurence Fishburne’s creepy and believable turn as a casino boss is salvageable but is too little, too late for the slow and drawling movie.

Ultimately, “21” is too long, and the gimmicky tricks it uses to capture the audience’s attention (glamour shots of Vegas, card-counting montages) deteriorate into monotony far sooner than they save the other aspects of the film. Somehow, “21” fails to make even gambling and sex appear exciting.