Ben Campbell (JIM STURGESS) is a smart kid who's attending M.I.T. with dreams of going on to Harvard Medical school, but is poor just like his best friends and fellow students, Miles (JOSH GAD) and Cam (SAM GOLZARI). His smarts in class, however, have drawn the attention of one of his professors, the student-friendly and charismatic Micky Rosa (KEVIN SPACEY). But the instructor is interested in more than just educating the young man, as he senses a highly useful and rare ability in him.
And that's the ability to count cards, a legal but highly frowned-upon activity where rapt attention, a calculating mind, and helpful teammates can translate into big money at Vegas casinos. Ben initially turns down the offer, but he needs $300,000 for his next school and doesn't want his mom's hard-earned life savings that she offers him.
Besides, one of his potential teammates, Jill Taylor (KATE BOSWORTH), is cute and alluring, so Ben decides to give it a go, promising himself that he'll stop when he earns the money he needs. Accordingly, he joins Rosa and his young accomplices that include Jill, Choi (AARON YOO) and Kianna (LIZA LAPIRA), although former star pupil-cum-counter Fisher (JACOB PITTS) isn't happy that Ben's around.
The same holds true for loss prevention specialist Cole Williams (LAURENCE FISHBURNE). While his type are quickly being replaced by sophisticated computer systems, Cole is employed by the casinos to use old school intimidation to persuade anyone caught counting cards to give up their endeavor.
Unfortunately for Ben, he's really good at just that. From that point on, and as he becomes both conceited and greedy, he must contend with his actions as well as the reactions of others toward his success.