The movie opens in the Namib Desert. Mr. A (Hrithik Roshan) skydives onto a train that is carrying the Queen. He steals her crown by disguising himself as the Queen, beats her guards easily, and escapes.
Newly promoted officer Ali Khan (Uday Chopra) and Jai Dixit (Abhishek Bachchan) are introduced to Shonali Bose (Bipasha Basu), a special officer assigned to investigate Mr. A’s case, who also happens to be a former classmate of Jai. After the initial investigation, Dixit analyses the underlying trend in Mr. A’s heists. He concludes that a theft will follow in one of two famous Mumbai city museums.
When Dixit realizes that the artifact in the museum he is guarding happens to be imperfect, he rushes to the other museum, where a disguised Mr. A steals a rare diamond and escapes. In a television channel, Mr. A challenges the police that he will steal an ancient warrior sword. In response, Dixit, Bose, and Khan enforce a strict guard at the location of the sword. At night, Mr. A meets a doppelgänger in the room that holds the sword. The police are alerted, but they manage to steal the sword and escape. The impersonator turns out to be Sunehri (Aishwarya Rai), a woman who idolises Mr. A; Sunehri convinces Mr. A to form an alliance.
In Rio de Janeiro, Mr. A and Sunehri plan their next heist. As Dixit’s analysis has named Rio the location of Mr. A’s next heist, Jai and Ali travel to the city. There they meet Monali (Bipasha Basu), Shonali’s twin sister, and Ali immediately falls for her. Meanwhile, the relationship between Mr. A and Sunehri evolves into romance and he unveils his real identity, Aryan, to her. However, he sees Sunehri and Jai together and realizes that Sunehri has been working undercover for Jai. Aryan forces Sunehri to play a game of Russian roulette. Sunehri cries and refuses to shoot Aryan because she loves him, but Aryan forces her to play. After six attempted shots from the gun, neither is injured, because Aryan has not loaded the gun. Sunehri admits she betrayed Aryan and confesses her love for him. In their final heist, Aryan and Sunehri successfully steal some early Lydian coins while disguised as performing dwarfs. Sunehri indicates that she does not wish to remain allied with Jai, forcing Jai and Ali to go after them. After the chase, all of them end up on the top of a waterfall, where Ali catches Sunehri. Sunehri, despite conveying her feelings for Aryan, shoots him. Aryan falls from the waterfall, after which Jai allows Sunehri to go free.
After six months, it is revealed that Aryan has survived and now has opened a restaurant in the Fiji islands with Sunehri. Jai meets Aryan and Sunehri at the restaurant and states that despite their crimes, he does not wish to imprison the couple. Aryan shows him where all the stolen artifacts can be found. Jai is aware of the couple’s feelings towards each other, but warns them against returning to their life of crime. Jai informs Ali that they should be heading back to India for their next case.