MIT senior math major Ben Campbell (Sturgess) is accepted into Harvard Medical School but cannot afford the $300,000 cost. Despite boasting a 44 MCAT score and a 4.0 GPA, Ben faces fierce competition for the prestigious Robinson Scholarship which would provide a "free ride" through medical school. He is told that he needs a way of "dazzling" Harvard in some way to stand out from the other extremely well-qualified applicants.


One day in math class, Professor Micky Rosa (Spacey) challenges Campbell with the Monty Hall problem, which Campbell solves successfully by using variable change and simple math. Seeing talent, Rosa invites Campbell to join his blackjack team, which consists of fellow students Choi (Yoo), Fisher (Pitts), Jill (Bosworth) and Kianna (Lapira). The system involves card counting, and the team—shepherded by Rosa—is split into two groups. "Spotters" play the minimum bet and keep track of the count. They send secret signals to the "big players," who place large bets whenever the count at a table is favorable. Campbell is unsure at first, but decides to join the team, telling Rosa he is only doing so until he can pay for medical school.


Rosa takes the team to Las Vegas over many weekends; Campbell comes to enjoy his luxurious lifestyle there. His performance as a "big player" impresses Rosa, but Fisher becomes jealous at Campbell's blackjack success. Rosa kicks a drunken Fisher off the team after he insults Campbell and incites a melee that requires the team to quickly "cash out" (using dancers from their usual strip-club meeting place) before the casino switches chips. Ben and Jill also develop a mutual attraction, which culminates in the pair having a sexual encounter in Jill's suite. Meanwhile, security chief Cole Williams (Fishburne) and his sidekick Terry (McGee) monitors the blackjack team, particularly Campbell.


Campbell, distracted by blackjack, botches his part of a project for the 2.09 engineering competition, estranging him from his pre-blackjack friends. During the next trip to Vegas, an emotionally-distracted Campbell continues playing even after he is signaled to walk away, losing $200,000. An angry Rosa leaves the team and demands Campbell repay him for the loss. Campbell and his three remaining teammates agree to go into business for themselves. On their first attempt, however, Williams apprehends Campbell (having been anonymously tipped off by Rosa), physically assails him, then lets him go after giving him a death threat.