The film picks up five years after the conclusion of Don. In a stylish rendezvous, the European drug cartel bosses gather on a luxurious yacht in the French Riviera to discuss a looming threat from Asia: Don (played by Shah Rukh Khan), who poses a significant risk to their illegal black market empire by dramatically lowering the prices of cocaine. Having already dominated the Asian underworld, they decide he must be eliminated. Meanwhile, in a secluded hideout in Thailand, Don prepares to make a clandestine pickup of cocaine but is quickly ambushed by his former allies. They reveal their treacherous plot—after eliminating him, they intend to claim the lucrative cocaine market in Europe for themselves. In a fierce contest of survival, Don retaliates, dispatching his adversaries and leaving the entire settlement in ruins.
Now a wanted fugitive, with Interpol on his tail and enemies lurking at every corner, Don suddenly surrenders to Roma (portrayed by Priyanka Chopra)—now an Interpol agent—and Inspector Malik (played by Om Puri), who is compelled to delay his retirement due to Don’s unexpected arrival. Inside the interrogation room, Don demands full amnesty for his extensive criminal record in exchange for critical intel on his business associates and the drug cartels. However, Malik makes it clear that he can only shield Don from the death penalty, firmly denying any reduction of his prison term.
After refusing to cooperate further, Don is condemned to death and transferred to a high-security prison in Malaysia. Here, he has a tense reunion with his long-time adversary, Vardhaan (played by Boman Irani), who seeks revenge for his own imprisonment at Don's hands five years ago. Initially, they clash like fierce combatants, but an unlikely partnership forms when Don offers Vardhaan a chance for freedom. Together, in a precarious alliance, they hatch an escape plan, disguising themselves as paramedics and poisoning fellow inmates to flee the facility.
In Zurich, Don reconnects with his loyal companion Ayesha (played by Lara Dutta). They unearth alarming evidence—a recording implicating J.K. Diwan (played by Alyy Khan), the Euro-printing DZB vice-president, in a scheme to murder James Werden and manipulate the bank's leadership. Diwan had conspired to secure the presidency for Fabian Kohl by bribing Singhania (portrayed by Rajesh Khattar) to eliminate Werden. The tape, which captured Diwan’s deceit, is now in Don's possession, allowing him to blackmail Diwan and acquire the blueprints for the bank’s vaults.
As Don meticulously prepares for the heist, Diwan's reluctance leads him to provide counterfeit blueprints. A deadly assassin, Abdul Jabbar (played by Nawab Shah), is sent to terminate Don. However, Don manages to turn Jabbar to his side through coercion. Despite Vardhaan urging caution against including Jabbar in their heist, he covertly informs Jabbar of Don's plans, laying the groundwork for a double-cross.
Meanwhile, Roma and Inspector Malik are hot on Diwan’s heels in Berlin but find no incriminating evidence with him. As Don embarks on the bank heist, tensions escalate. After the robbery, Vardhaan and Jabbar betray Don but fail in their attempts to capture him, allowing Don to escape through the sewers with the help of his hacker companion Sameer (played by Kunal Kapoor).
In a final act of cunning, Don negotiates a deal with German authorities, proposing to surrender the printing plates in exchange for immunity from prosecution and the safety of hostages being held. He tears down Vardhaan and Jabbar’s scheme while revealing a change of heart to Roma, stating he seeks to exit his criminal life for good in efforts to save lives.
The film culminates in a high-stakes showdown where personal relationships are tested. In a tense moment, Roma refuses to kill Don, despite her ties to a tragic past. As chaos erupts, Don fiercely retaliates, culminating in a brutal confrontation with Vardhaan and Jabbar, leading to Vardhaan's return to custody and Jabbar's downfall.
Ultimately, Don skillfully manipulates the system, presenting fake evidence and protecting the real printing plates. As allies gather, he reveals his grand plan, stating they have no idea of the wealth and power awaiting them. In the final moments, Don emerges as the undisputed kingpin of the European underworld—a free man, basking in riches, as he prepares for a future of untold wealth with Ayesha and Sameer by his side.
