An unconvincing exercise in moral complexity, 21 is based on Ben Mezrich's book Bringing Down the House: The Inside Story of Six M.I.T. Students Who Took Vegas for Millions. Jim Sturgess () plays brilliant blue collar scholar Ben Campbell, whose doubts that he'll win a scholarship to Harvard Medical School compel him to join a secret, M.I.T. gang of math whiz kids. Under the silky but chilling command of a math professor (Kevin Spacey), Jim and the others master card counting --the statistical analysis of cards dealt in blackjack games. The team lives a humdrum existence during the week, but on weekends in Sin City the students are rolling in cash, frequenting exclusive clubs and feeling on top of the world. Ben even gets the girl: a comely fellow card counter played by Kate Bosworth. Despite all the success, Ben feels ethically compromised and indeed director Robert Luketic (, ), in the old tradition of American movies, plays it both ways where fun vices are concerned. On the one hand, it feels so good --on the other, ahem, we know it's wrong. That studied ambivalence proves wearing after a while, making the most interesting character in the film a casino watchdog played by Laurence Fishburne. A master at reading the emotions of gamblers beating the house with a scam, he's admirable for being good at his job, but repellent for wrecking the faces of counters in casino dungeons. He's all about moral complexity in the tradition of anti-heroes, and a truly provocative element in an otherwise superficial movie. --Tom Keogh