The police arrest Sakthivel “Velu,” the son of an anti-government union leader, in their attempt to locate him. Through deceit, they make Velu believe they are his well-wishers and release him. Upon reuniting with his father, the police kill the elder man, leaving Velu feeling betrayed. Reacting to this betrayal, Sakthivel stabs a police inspector and flees to Bombay. There, he finds refuge with Hussain, a compassionate smuggler residing in Dharavi slums. When Hussain falls ill, a young Velu takes on smuggling to support him. However, his demand for a larger cut angers the smugglers, leading them to involve Inspector Kelkar to arrest Hussain, ultimately leading to his death in prison, which is later ruled as suicide. Learning the truth incites Velu’s rage, prompting him to kill Kelkar. Velu assumes responsibility for Kelkar’s family, including his wife and his mentally challenged son Ajit. Kelkar’s wife had been aware of her husband’s unethical actions, which contributed to his demise.
Velu’s life takes another turn as he crosses paths with Neela, a schoolgirl forced into prostitution who aspires to pursue an education. Her bravery and purity deeply impact Velu, leading to their marriage and the birth of two children: Surya and Charumathi. Velu’s influence grows in Dharavi as he advocates for the local people, winning their support. He becomes a revered figure, but rival smugglers attempt to assassinate him. Tragically, Neela is killed in one such attack. Seeking retribution, Velu sends his children to Madras for safety.
Years pass, and Velu’s power in Bombay strengthens, earning him the affectionate moniker “Velu Naicker.” Surya and Charumathi return as adults after completing their education. Surya hesitantly follows in Velu’s footsteps, eventually accepting his path. However, when Surya dies while attempting to evade the police during a failed mission, Charumathi blames Velu for the deaths of both Neela and Surya. Disillusioned, she distances herself from her father’s violent world, disowns him, and departs Bombay. A new Assistant Commissioner of Police (ACP) named Patil is assigned to eradicate gangsters, and Velu becomes his prime target. Patil gathers evidence against Velu and discovers that his wife Charumathi is Velu’s daughter, raising suspicions about her potential involvement.
As Velu evades capture, his allies are apprehended. To spare them from police mistreatment, Velu decides to surrender, arranging this through Charumathi. However, the lack of public witnesses makes the case against Velu weak, shocking Patil. He seeks the truth about Kelkar’s death from Kelkar’s widow and Ajit. While Kelkar’s widow defends Velu’s actions, Ajit is disturbed by the revelations. Velu is brought to court and is acquitted due to insufficient evidence. Emotionally moved, he meets his grandson Shaktivel, Charumathi’s son. Amidst cheers from supporters, Velu exits the court, only to be fatally shot by Ajit seeking vengeance for his father’s death. Velu succumbs on the spot.
