If the excitement of gambling were really about winning, there would be few gamblers to support the multibillion-dollar gambling industry. Everybody knows that the odds are fixed to favor the house and that people play the games for the rush, not the payoff. Bettors are many; winners are few. That’s what makes it a probably successful business, like insurance. The rewards for competing in the game exceed the payouts the company makes as incentives to keep the players playing.

So how exciting would it be if, say, somebody devised a system that used simple math to give a blackjack player the advantage over the dealer? Inspired by the real-life story of the six M.I.T. students who took Las Vegas casinos for millions, 21 was reshaped to fit a simple movie template and it’s nearly as much fun as watching an insurance professional compute actuarial tables.

21 is a perfect case of how something that’s “based” on a true story can nonetheless exist mainly in the realm of fiction. While it’s true that the source material for the movie, Ben Mezrich’s Bringing Down the House relates events that actually happened, screenwriters Peter Steinfeld and Allan Loeb have fictionalized the entire story, leaving intact only the central idea that a group of MIT students devised a card-counting scheme that allowed them to swindle the Vegas casinos. And, while I’m a firm believer in the adage “Never let the truth get in the way of a good story, 21 doesn’t spin a good enough story to support all the changes. In fact, when one character shows to another that he started out smart then got clumsy and stupid, he might have been referring to the script.

In 21, the worst thing a gamester can be blamed for is gambling. “Don’t give in to your emotions,” M.I.T. professor Micky Rosa tells his blackjack students. “Play the system.” Good suggestion for a card-counting scheme and bad suggestion for a movie. If you want to see how a script looks when it’s actually on the screen, 21 may provide a practical lesson: How to follow all the “rules” and end up with zero. It’s not unwatchable, but you could watch it with your eyeballs tied behind your back and enjoy it just as much.

Our “entry point” into 21 is Ben Campbell (Jim Sturgess), a graduating MIT senior who has already been admitted to Harvard Med School. There’s a problem, though: Ben can’t raise the needed $300,000 and his chances of getting a “free ride” scholarship appear slim. Along comes Professor Micky Rosa (Kevin Spacey), who brings with him a too good to be true offer: space has opened up on his team, and he’s offering it to Ben, one of the most gifted mathematical minds he has encountered during his time teaching at MIT. A team is a group of five students who visit Las Vegas regularly and put into effect a sophisticated card-counting scheme that the casinos have been unable to break. Initially, Ben refuses, but the allure of Harvard Med plus his attraction to Jill Taylor (Kate Bosworth), one of Micky’s special students, pull him in. After a local start, it’s off to Sin City for Ben’s official induction. There, waiting to match wits with him is Cole Williams (Laurence Fishburne), the head of security at Planet Hollywood.

Here’s another example of a good story turned into a purely generic one — no doubt with the help of a Bob McKee screenwriting seminar and textbook.

Act I:

M.I.T. undergrad Ben Campbell (Jim Sturgess) is a nerdish wicked-smart Bostonian white guy working with his best friends (a fat guy and a Persian-American guy) on a project for a robotics competition. He needs a $300,000 scholarship to get into Harvard medical school, but he’s only one of 72 talented prospects. He’s recruited by Professor Rosa (Kevin Spacey) to join a secret cabal of card-counters with a scheme to hit Vegas on weekends and make a fortune. He resists. A Beautiful Girl (Kate Bosworth) attempts to encourage him. He opposes. OK, he needs the money, so he joins up but just until he can get enough for full college tuition.

He learns the blackjack system in a montage sequence or two and passes the test. The beautiful girl rebuffs his advances to maintain a strictly professional relationship.

Act II:

The team goes to Vegas, and the guys win. Another montage sequence? Maybe, it’s getting a little fuzzy. But wait: A casino security guy named Cole Williams starts to notice something and not a moment too soon because he’s losing all his business to high tech biometric face recognition software. Card-counting isn’t illegal, but the casinos want you to know that if you’re caught doing it, they might take you down in the basement and beat the living craps out of you.

The beautiful girl retracts her rebuff. The Hard Rock Casino comps her suite in which she and Ben enjoy a brief, soft-focus scene montage. “It seemed too good to be true,” Ben says in voiceover. “And it felt like it was never going to end.” It does. Ben is no longer the same guy he was back in Boston. He loses money, his friends, the beautiful girl, his mentor, everything.

Act III:

Ben has one last chance. He makes up with Rosa and the girl, and the team reunites for one final Big Score in Vegas. Everything works out exactly as the screenwriters have planned.

The idea behind 21 is compelling – tell how a group of college kids beat one of the most sophisticated anti-crime systems in place anywhere around the world. Unfortunately, the problem is with the execution. Perhaps because there’s math involved, 21 doesn’t do an adequate job of providing the bare-bones details of how the crime is pulled off. It hedges and cheats and employs lots of quick edits, but we don’t get anything close to a logical story of what the kids’ methods are. It doesn’t take long before the film relegates the heist elements to the setting so it can focus on clichéd interpersonal relationships, including a romance between Ben and Jill. Ultimately, the movie ends with a series of Hollywood staples, including a chase and a “twist” that won’t surprise anyone.

21 is yet another example of Hollywood dumbing-down smart people. To pull off something as daring and successful as what the MIT students did, they had to be geniuses. As portrayed in the movie, they’re unimpressive blunderers. Some of the things they do are so stupid that they’re insulting. Of course, these characters are ultimately going to get caught doing these sorts of things. How could they not? Audiences enjoy watching heist movies where the characters are two steps ahead and where the narrative provides some surprises. Neither characteristic is evident here. And, also, the resolution has an unpleasant quality. The fingerprints of those demanding a Hollywood ending are all over this screenplay.

Jim Sturgess, who survived Across the Universe relatively unscathed, gives a nice turn as shy Ben, who gradually emerges from his shell as he gains more confidence in his newfound skills. It’s a familiar character arc, but Sturgess’ performance allows us to buy into it. Kevin Spacey provides his customary intensity; he’s fun to watch even when he’s not in peak form. His superman returns co-star, Kate Bosworth, isn’t as successful. Her performance is wooden, and she and Sturgess don’t click as a couple. Laurence Fishburne is wasted in a stereotypical thug role, and no one else has enough lines to be worth mentioning. The supporting characters in 21 genuinely are one-dimensional and the pace is glacial. The high-energy Vegas setting doesn’t boost the wattage of the production. The movie is a little over two hours in length but feels longer. Some of the movie’s last-act “action” sequences have been inserted initially as a way to liven things up, but they’re so pointless and imitative that all they do is drag out the running length.

Perhaps most hilariously, the movie itself has a tell: Watch for the moment when somebody naturally pulls a punch. If you hadn’t figured out the rest of the film by then, it gives away the whole thing.

“21 is great for Vegas, it affects the myth that blackjack is beatable.”