Journalist Anand Ingalagi's book El Dorado, which detailed the events at the Kolar Gold Fields (KGF) between 1951 and 2018, was banned by the Indian government, but a television news channel procures a copy and interviews him.
In 1951, Raja Rocky Krishnappa Bairya is born to a poor, underage girl named Shanti. On the same day, government officials, accompanied by Suryavardhan, arrive to investigate a strange yellow rock discovered by workers digging a well in southern Mysore State. Upon realizing that the rock was gold ore, Suryavardhan, a powerful don and politician of the time, kills the officials and leases the land for 99 years under the pretext of running a limestone mine called Narachi, while secretly establishing K.G.F and his crime syndicate. To manage the empire, Suryavardhan had appointed five associates: Adheera, his ruthless younger brother, who headed the security at K.G.F; Kamal, son of Suryavardhan's late associate Bhargav, who looks after gold refinery in Varca; Rajendra Desai, who oversees the transportation of gold bars coming from the refinery; Andrews, who oversees the gold smuggling in the Western Coast; and Guru Pandian, president of the incumbent DYSS party who gave political influence to Suryavardhan. Suryavardhan suffers a stroke and appoints his elder son Garuda as the future heir of K.G.F, expecting Adheera to serve as his son's aide. His associates, now eyeing the riches of K.G.F, plan to assassinate Garuda. Adheera is presumed dead after Garuda bombs his car in retaliation for Adheera's unsuccessful assassination attempt.
Rocky arrives in Bombay as a ten-year-old on a quest for wealth and power as desired by his dying mother, and begins to work for Shetty, a gold smuggler and Andrews' underboss, who competes against a Dubai-based underworld don Inayat Khalil. Years later, he rises in ranks and oversees the arrival of gold bars to the Bombay coast. Andrews notices Rocky's influence has begun to rival Shetty's own, and offers Rocky complete control of the Bombay underworld in return for assassinating Garuda. Rocky accepts the offer and heads to Bangalore, where Suryavardhan's statue is built at the DYSS party office to lure Garuda out of K.G.F. Desai, Andrews, Kamal, and Andrews' secretary Daya covertly smuggle in a pistol for Rocky, but the attempt is foiled when they are spotted by Garuda's bodyguards. Garuda reveals he had replaced his father's statue with his own. Rocky, witnessing the authority and power that Garuda commands and seeing no other option to murder him, decides to journey to K.G.F. The workers in K.G.F, who are forcibly kidnapped from nearby villages, are subjected to inhumane conditions and treated as slaves. Rocky allows himself to be kidnapped and enters K.G.F with other slaves. Rocky stealthily accesses the map of the mine in the maintenance room during a roll call and narrowly escapes death after a fellow slave sacrifices himself to save the lives of his wife and unborn child. Andrews, Kamal and Desai are misinformed about the incident and assume Rocky is killed.
Although apathetic at first, he is moved by the cold-blooded murder of a mother and son by a guard. Rocky engages in a fight with an entire unit of twenty-three guards, killing each one of them to save a blind slave. With this act, Rocky emerges as a messiah in the slaves' eyes. He orders them to burn the guards' corpses to let Andrews and his men know he is still alive via their informants, Kulkarni and Garuda's younger brother Virat. Garuda prepares to leave his residence to investigate the fire and missing guards. To avert this, Virat smothers Suryavardhan to death, in order to sidetrack Garuda, who rushes back home. Rocky heads unsuspected through a tunnel from the mines to Garuda's mansion, following the map in the maintenance room.
Shaken by the recent bad turn of events, Garuda orders Maa Kaali's ritual, to be rescheduled from the following week to the next day. Garuda plans to kill his father's allies as soon as the ritual, where he has decided to behead three assassins (sent earlier to kill him) as offerings to the goddess, is completed. The next day, while preparations for the ritual are being made, Vanaram, the head of security, discovers one of the assassins dead inside his prison cell, and realizes someone has entered the mansion. As Garuda beheads two assassins, Rocky, who hid himself as the third assassin, emerges and beheads Garuda. The ecstatic slaves accept Rocky as their leader.
Ingalagi concludes that Rocky intentionally chose K.G.F as the location to assassinate Garuda, thereby inspiring an army of slaves to help him seize control. He indicates, however, that this is just the beginning. The news of Garuda's murder reaches Inayat Khalil and Ramika Sen, the to-be prime minister of India. Adheera, who is revealed to be alive, hears the news of Garuda's death and plans to resurface. All others at the K.G.F including Desai, Kamal, Andrews, Daya, Khalil and Shetty, were overjoyed by hearing the news. As Vanaram orders his men to attack Rocky and his army, a gunshot is heard.
