David Billa (Ajith Kumar), a Sri Lankan Tamil refugee along with several others, arrives at the town of Rameswaram in boat. After being interrogated by an arrogant civil servant, he is let into the refugee camp where he befriends Ranjith (Yog Japee). David makes his presence felt, when he slaps Muthu (Theepatti Ganesh) one of the rogue workers around for making a derogatory comment. The refugee camp is constantly terrorised by a corrupt police officer Raghubir Sinha (Krishna Kumar).
After witnessing the brutal murder of one of the inmates at his hands, David attacks Raghubir when he tries to forcefully detain one of his friends. Raghubir then gets David tortured in prison, and vows to make him suffer. A few days later, Muthu calls David and Ranjith aside and promises them work. Billa and Ranjith are hired to transport fish from Rameshwaram to Chennai. But unknown to them, the truck they were driving had diamonds inside, and Raghubir had alerted his men on the highway to catch them red-handed. As per the plot they get caught in the check post, and after realising what had happened, Billa kills all the cops and drive the truck to its destination. Here they meet Selvaraj (Ilavarasu) who is pleased by Billa’s loyalty and includes him in his businesses. Billa gets back and murders Raghubir as well as the arrogant civil servant he had initially met at the camp. He then goes to meet his elder sister (Janaki Sabesh) and his niece Jasmine (Parvathy Omanakuttan) in a church. When they see his gun, they realise that he is involved in crime. Not knowing what to say, Billa simply walks away.
Kotiswara Rao(Manoj K.Jeyan) visits Selvaraj and asks him if he could help in selling off the cocaine he had brought along with him. Billa volunteers to sell it off on a five percent commission in exchange. Billa sets off and delivers the cocaine to a local thug who however refuses to pay for it in return. In a brutal scuffle that ensues, where one of Billa’s friends is slaughtered, Billa takes out the thug and his men and returns with both the money and the cocaine. Soon Billa meets Koti’s boss Abbasi (Sudhanshu Pandey) who is very impressed by the former and recruits him. After a party held at his club he receives a phone call from the Russian mafia led by Dimitri (Vidyut Jamwal) telling him that his arms consignment has been held by the Indian coastal guards and he asks for his help. Billa and Ranjith retrieve the consignment for him. Both are congratulated by Dimitri for their work.