Vishwa is a dancer who lives in Sydney, Australia and also manages a water distribution business in the name of his deceased mother Ganga there with his childhood friend Logu and his dance team members. He is the son of Ramadurai, a Mumbai-based don who fights for rights of the Tamil-speaking migrants in the city. Ramadurai, fearing for his son’s safety since Ganga’s murder at the hands of rivals, had sent him away to Australia via Ratnam, his friend. Although they are in regular contact, Ramadurai lies to Vishwa that he is a businessman.
Vishwa falls in love with Meera, the daughter of a restaurateur, who is one of his customers. Meera reciprocates Vishwa’s love and joins his dance team, helping them win a dance competition. She soon proposes marriage to Vishwa, who agrees. Meera’s father too agrees to the marriage but wants to discuss the matter formally with Ramadurai. They leave for Mumbai, where Vishwa finds out about his father’s true identity and that he is currently in hiding due to several false cases registered against him by his archenemy, another don Bhima Bhai. This is because Ramadurai murdered Bhima’s father for killing Ganga, so Bhima swore revenge. Vishwa also finds out that Meera and her “father” are officers of the crime branch who lured him to Mumbai so that they could locate and arrest Ramadurai. Ramadurai is arrested, but just after he enters the police van, a bomb planted by Bhima in the van explodes, killing him. Vishwa is distraught over his father’s death and decides to stay back in Mumbai and take over his father’s crime syndicate. He dons the title of Thalaivaa and provides his own brand of justice for the helpless and downtrodden.
Meanwhile, Bhima instigates riots in Mumbai which kill many people and leave several others injured. Vishwa arrives at the scene and saves several others, including Gowri, a Bhojpuri woman who marriage was nullified due to the riots. Although there is seemingly no evidence that Bhima is responsible, a tape recorded by a cameraman Video Kumar, highlighting Bhima’s involvement in the riots is stolen by a Bhojpuri-speaking pickpocket. Vishwa and his gang manage to reclaim the tape from the pickpocket and publicize it, leading to Bhima’s arrest. Vishwa also kills the corrupt Chief Minister of Maharashtra, who had given Bhima and his gang free rein, and puts the blame on Bhima. However, Bhima soon escapes from prison and kills most of Vishwa’s henchmen on the night of Maha Shivaratri including Gowri, with the help of Vishwa’s uncle Ranga, who is Vishwa’s second-in-command. When Vishwa enters a fort after hearing Ranga is being “held hostage” there by Bhima, he is stabbed by Ranga, who immediately informs the police that Vishwa is “dead” and leaves the fort with his physically handicapped son, who is Vishwa’s cousin and driver. When Ranga’s son hears about his father’s treachery, he becomes enraged and drives the car into a petroleum tanker, killing them both. Meanwhile, Vishwa, though injured, is still alive. After a bitter fight, he kills Bhima by stabbing his throat. Meera soon arrives at the fort and realizes that Vishwa killed Bhima, but she acts quickly and shoots the corpses of Bhima and his henchmen to imply that she killed them, thus saving Vishwa from a jail term.
Meera eventually quits her job as a police officer after realizing her love for Vishwa, and marries him. With Bhima and his gang out of the way, Vishwa is now the unchallenged don in Mumbai.