MI6 Agent James Bond achieves his double-0 agent status and goes in pursuit of a dangerous target named Le Chiffre, a criminal mastermind who sells stock in profitable companies and then sabotages their share prices. In Miami, Bond ruins Le Chiffre's plan to bring down a prototype airliner. Now in need of money to pay off debts to his terrorist clientele, Le Chiffre hosts a high-stakes poker game at Montenegro's Casino Royale. MI6 enters Bond into the game, hoping that Le Chiffre can be manipulated into giving information to MI6 if he loses the game and has nowhere else to turn for protection afterwards.
Traveling to Montenegro Bond meets Vesper Lynd, the Treasury agent in charge of his ten million dollar buy-in to the game. At the Casino Bond loses his initial stake. When he is unable to buy back in, an angry Bond decides to ignore his orders and assassinate Le Chiffre. Another player tells Bond that he is actually a CIA agent and will front Bond the money he needs to return to the game in return for custody of Le Chiffre. Bond begins winning at poker only to be poisoned by Le Chiffre's henchmen. He survives thanks to Vesper and goes on to win the tournament but Le Chiffre abducts Vesper in revenge, hoping to use her in order to capture Bond.
Le Chiffre tortures Bond to get the code to the Swiss bank account holding Bond's poker winnings. Criminal Mr. White appears and rescues Bond by killing Le Chiffre. When he awakes in a hospital on Lake Como, Bond turns over a double agent identified by Le Chiffre to his superior M. He tells M that he's in love with Vesper and gives his resignation to MI6 so that he can be with her. The pair goes to Venice where he finds out that Vesper stole his winnings. In his pursuit of Vesper and the organization she's working for, the woman is killed in a collapsing building. Mr. White, now in possession of the money, watches the fight and departs. With his lover dead, Bond returns to MI6 and learns that Vesper did not truly betray him but was blackmailed. The film ends as Bond begins a hunt for Mr. White.