In Kuala Lumpur, Malaysia, the Asian illegal drug trade is thriving under the leadership of Sanjeev Singhania [Rajesh Khattar], one of Boris’s trusted lieutenants who keeps the cartel running with ruthless precision. The criminal empire is controlled from the shadows by Don [Shah Rukh Khan], a powerful and elusive figure whose reach stretches far and wide. Deputy Commissioner of Police D'Silva [Boman Irani] leads a dedicated task force that aims to capture Don and dismantle the organization once and for all. Don murders Ramesh [Diwakar Pundir], a gang member who tries to walk away from the life, sending shockwaves through the operation. Kamini [Kareena Kapoor Khan], Ramesh’s fiancée, makes a desperate bid to aid the police in luring Don into a trap, but she too is killed. Roma [Priyanka Chopra Jonas], Ramesh’s sister, chooses vengeance over safety and willingly joins Don’s faction to avenge both her brother and Kamini.
After a failed police operation leaves Don gravely injured and slipping into a coma, D'Silva seizes the opportunity to strike from the inside. He recruits Vijay, a simple but skilled lookalike from Mumbai who can pass as Don, and promises to arrange schooling for Deepu [Tanay Chheda], a child Vijay cares for, to win his loyalty. Jasjit [Arjun Rampal], Deepu’s estranged father and a former IT professional, has just been released from prison; years earlier he was forced into stealing diamonds to rescue his kidnapped wife, but the authorities didn’t believe his story, and his wife died in the ordeal. This painful history fuels his desire for revenge and complicates the mission from the start.
In the hospital, Vijay undergoes surgery to transform into Don, and when Don dies of a cardiac arrest, Vijay steps back into the criminal world with a fresh alias to carry out the mission. D'Silva tasks Vijay with recovering a disc that contains critical details about the cartel’s operations. Roma tries to kill him, but D'Silva intervenes and reveals Vijay’s true identity to her. Vijay succeeds in obtaining the disc and hands it over to D'Silva, who later orchestrates a nightclub raid that results in Singhania’s death. The aftermath leaves D'Silva wounded and Vijay isolated, with no one willing to vouch for his true identity. He is arrested and then escapes during a prison transfer, setting out to prove his innocence to Roma.
Meanwhile, Jasjit discovers the disc in D'Silva’s apartment but is forced to trade it for Deepu’s life when his captors tighten their grip. He uncovers a startling truth: D'Silva is alive and operating under the alias Vardhaan, Boris’s second-in-command who orchestrated the entire plan to crush Singhania and seize control of the cartel. Jasjit rescues Deepu and teams up with Vijay and Roma to expose the conspiracy, eventually informing Interpol, which leads to Vardhaan’s arrest after a tense confrontation with Vijay.
With his name cleared, a wounded Vijay is taken to the hospital where Roma confesses her love for him. He answers with warmth, but she soon realizes—too late—that he is not truly Vijay. In a final twist, it’s revealed that Don is alive and had been impersonating Vijay all along during the hospital encounter. Don had recovered from his coma earlier, overheard D'Silva and Vijay’s plan, swapped places with Vijay after the surgery, and later murdered him with a fatal dose of diazepam to fake Don’s death. The disc he surrendered to authorities was a fake. With Singhania and Vardhaan eliminated, Don reclaims his identity and resumes his position at the head of the Asian drug cartel.
