In the year 1795, the Indian subcontinent, then referred to as Hindustan, was under the oppressive rule of the British East India Company. The brave King Mirza Sikander Baig (Ronit Roy) of Raunakpur tirelessly defended his realm against its greedy designs. The formidable officer John Clive (Lloyd Owen), represents the ruthless ambition of the East India Company, which has its eyes set on conquering Mirza's kingdom. In a desperate attempt to gain assistance, Mirza sends his loyal general Khudabaksh (Amitabh Bachchan) and his son Aslam (portrayed by Sharad Joshi) to seek help from the allied Kingdom of Durgapur. However, with Khudabaksh delayed in his mission, Mirza feels compelled to take matters into his own hands and preemptively attack the company's stronghold.
Just as Mirza prepares for conflict, Clive storms into the palace with a battalion at his command, anticipating Mirza's assault. To force the king into submission, Clive uses the young Aslam as leverage, binding him to a cannon as a cruel ultimatum. Upon signing the treaty under duress, tragedy strikes when Clive coldly executes Aslam. In the chaos that follows, Mirza is killed, and his kingdom is left in ruins, overrun by British forces. Only Zafira Baig (Fatima Sana Shaikh) and Khudabaksh manage to survive, with Khudabaksh adopting Zafira as his own daughter and training her in the art of warfare.
Fast forward eleven years to 1806, and Khudabaksh, now known as Jahaazi, leads a fierce band of Thugs who specialize in sea combat, challenging the expanding British Empire. They boldly raid British ships, turning the tide against their colonial oppressors. Clive, now alarmed at the Thugs' rise, commands Captain James Powell (played by Gavin Marshall) to devise a strategy to eliminate this emerging threat. Not to be outdone, Maharaja Sangram Singh (Sharat Saxena), an ally of Clive, feigns opposition to the Thugs while secretly conspiring against them.
Enter Firangi Mallah (Aamir Khan), a cunning and untrustworthy conman whose schemes involve double-dealing both merchants and bandits alike. He becomes entangled with a captivating dancer named Suraiyya (Katrina Kaif). As Firangi is drawn into a web of treachery, the British enlist his aid against the Thugs, promising him a lavish life in exchange for his cooperation. He teams up with Shanichar (Mohammed Zeeshan Ayyub), a gifted astrologer and escapes with him from captivity.
A twist occurs when Firangi, having infiltrated a British ship with Shanichar, is discovered and faces peril. At this critical moment, Jahaazi arrives to combat the British forces. Despite his earlier profane selfishness, Firangi inadvertently saves Jahaazi’s life during the ensuing battle. As he recuperates in Jahaazi's sanctuary with the help of healer Jaitumbi (played by Ila Arun), Firangi maneuvers into a position as an informant for the British, revealing his internal struggle between loyalties.
As political machinations unfold, Sangram Singh's true allegiance to the Thugs is exposed. In a desperate attempt to solidify his power, Firangi betrays Jahaazi's trust by leaking plans to Powell. When Jahaazi engages in defending his territory against British assault, Firangi's conflicting motives come to light as he repeatedly intervenes to save his supposed foe. Tragically, Jahaazi's ship laden with explosives meets catastrophe during an attack—seemingly claiming his life, but leaving the idea of Jahaazi alive and thriving.
With vengeance in her heart, Zafira swears to seek retribution against Clive. Meanwhile, Firangi, deceiving both the British and the Thugs, finds himself in a precarious position. When Clive unveils his dastardly plans at the annual Dussehra festival, Firangi leads a combined effort to liberate Jahaazi but ultimately turns on his allies, exposing Zafira’s identity. Clive ruthlessly decides to execute Zafira at dawn, bringing the story to a climactic confrontation at Mirza's historic fort.
In this final showdown, Zafira and Jahaazi fight valiantly against superior British forces, but hope seems dim until Firangi and his companions intervene, dramatically shifting the battle in favor of the Thugs. Zafira manages to defeat Clive, delivering justice for her fallen family and nation. However, the tale takes a twist as Firangi, adapting the guise of a hero, seizes Jahaazi's ship and departs for England, with Suraiyya following, hinting at a future where the lines between loyalty and betrayal remain forever blurred.
