Plot

Roy Kapoor (Abhishek Bachchan) is a shameless conman. In fact, Roy's girlfriend Simi (Priyanka Chopra) too believes that he is an investment banker. One day he cons a film producer (Tinu Anand). Unfortunately, the producer turns out to be an acquaintance of Simi and thus Roy's true face is exposed. Simi calls their wedding off. Some weeks past this episode, Roy sees an amateur conman Dittu conning a doctor called Dr. Bhalerao (Boman Irani). Roy meets and foils Dittu's plans a couple of times, upon which Dittu (Ritesh Deshmukh) pesters Roy to become his mentor. Roy reluctantly accepts Dittu, a film buff.

One day, Roy starts experiencing blurring of eyes, unbearable headache and blackouts. Dr. Bhalerao diagnoses him with brain tumor and says he has only 3 months to live. Roy is shattered. He wants to reconcile with Simi, while she spurns him. When Roy sees her with somebody else, he resigns to his fate and turns his attention to Dittu. Dittu reveals that his father was a simple man who was conned of his life savings by a share market scam, apparently pulled by Chandru (Nana Patekar). Chandru is a whimsical but ruthless man. Roy decides to do use his skills for Dittu. When Roy sees a news footage about a robbery in a jewelry shop, Roy gets an idea to con Chandru.

Roy sends one of his men as police to Chandru to give him a list of serial numbers of all the notes stolen in the "heist"(which they have themselves printed). Then Roy and Dittu turn themselves up at Chandru's hotel as suspicious characters with lots of money. When Chandru is convinced that they are the thieves, he proposes to give them any amount for the stolen loot. They strike a deal with Chandru. They turn down the deal, which makes Chandru raise the price. Chandru privately arranges another deal with Roy: Roy gets full money if he kills Dittu. Roy apparently accepts the deal.

Meanwhile, Simi re-enters Roy's life after learning that he was indeed telling the truth about his condition. She has broken her marriage and wants to be with Roy in his last days. Their relationship blossoms again. She learns from Roy why he took up to being a conman. As per Chandru's deal Roy kills Dittu & tells Chandru to meet him in Maratha Mandir. It is revealed that Dittu is not dead, he has faked it as part of their con.

Chandru arrives with the money at the theatre as promised. But Dittu shows up behind them suddenly & shoots Roy to death, taking advantage of a shooting scene being shown. Dittu demands 5 Crore rupees at gunpoint from Chandru. Chandru arranges the money to be delivered before the film ends. After the payment, Chandru returns back & Roy is shown to be alive. The con arranged by Roy & Dittu has been successfully executed. Unfortunately, Omar, a man conned earlier by Roy, has seen the whole thing.

When Roy & Dittu are celebrating, Omar confronts the duo. Roy suddenly faces one more blackout while Omar runs away with the money. Roy has never told Dittu about his condition. When Roy opens his eyes, he is in Dr.Bhalerao's hospital. He sees a pained look on Dittu's face who has learned Roy's secret. Dr.Bhalerao tells Roy that his cure is possible abroad, but money is the problem. Roy withdraws all his life's savings. Suddenly, he gets a call from Simi. He answers but hears the voice of Chandru.

Chandru threatens him that if he doesn't return the money, Simi will suffer. Roy heads towards the rendezvous location with Dittu. He instructs Dittu to forget whatever Roy has taught him & live rest of his life as a reformed man. He also tells that he will see to it that Simi comes down safely, upon which Dittu should escort her to safety. Roy comes on the top floor to meet an angry Chandru. Chandru leaves Simmi but has a scuffle with Roy. He angrily pushes Roy from the roof.

Roy falls down, but instead of dying, ends up on an inflated plastic bed and survives. Confused, he turns towards people surrounding him, only to learn that they thought it was a film shoot. Roy tries to call everyone from Simi to Dittu and Chandru but gets no response. Then he realizes that he has been elaborately conned. After learning that he has no brain tumor, he heads to a place where he thinks everybody would be present. As expected, he meets everybody and as Dittu gives real introduction of every partner, Roy is left amazed.

Dr. Bhalerao is actually a vet while Chandru is the script writer for all the drama (who in reality is afraid of smallest of the things). Roy learns that Dittu is actually Arjun a film-director and is the son of the producer he had conned and that even Simi's second engagement was fake. Then, Dittu explains in detail how the whole operation was planned. After learning that it was Simi and Dittu's idea to teach him a lesson, Roy approaches and makes up with Simi.