Gifted poker player and law student Mike McDermott (Matt Damon) dreams of winning the World Series of Poker. At an underground Texas hold 'em game run by Russian mafia Teddy "KGB" (John Malkovich), an overconfident Mike loses his entire $30,000 bankroll. Shaken, he promises his girlfriend and fellow student Jo (Gretchen Mol) he has quit poker, and concentrates on law school. His mentor Joey Knish (John Turturro) offers to stake him to rebuild his bankroll but Mike declines, and instead accepts a part-time job to make ends meet.