Mickey Rosa (Kevin Spacey) is an MIT mathematics professor who recruits the brightest minds on campus to his classes. Dr. Rosa secretly teaches the trade of counting cards to the brightest kids in the hopes of cashing in on the casinos in Las Vegas. Ben (Jim Sturgess) is a mathematical genius, who quickly learns the secrets of the trade. Ben trades in the rigor of academia and Boston for the glamour of Las Vegas. Ben's skill is evident when slowly wins a large amount of cash. Along with him as part of the card-counting team are several classmates; Jill (Kate Bosworth), Miles (Josh Gad), Fisher (Jacob Pitts), Choi (Aaron Yoo), Cameron (Sam Golzari) and Stemple (Spencer Garrett).
The team employs an intricate, yet legal, system of signals in order to best determine which tables are statistically in favor of the player. The card-counters start to beat the casinos by getting huge pay outs during their weekend excursions. As the money grows, the stakes become higher, and the challenge becomes not only keeping the numbers straight, but staying one step ahead of the casino's enforcer, Cole Williams (Laurence Fishburne).