Tamizh (Vijay) is a ruthless, fearless hit man in the Chennai underworld. He climbs the mafia ladder much to the dislike of other members in the gang. But he maintains his principles, namely, never to harm women or children. He soon falls hook line and sinker for Shruthi (Asin Thottumkal), an aerobics instructor. But a corrupt police officer L Govindan starts to covet Shruthi and her honour is placed in the hands of the protective Tamizh. At the same time, she too becomes distraught that her lover Tamizh has such a cold-hearted and violent streak.
After a series of gang wars, the master mind of all crimes, international don Ali Bhai (Prakash Raj) lands up in Chennai from Dubai and appoints Tamizh as the new head of the gang. However, Ali Bhai is soon arrested and also released subsequently when his henchmen kidnap the honest City Police Commissioner’s (Napolean) daughter and exploit her. All this culminates in a rivetting climax where Tamizh is revealed to be none other than IPS officer Satyamoorthy, who had infiltrated the mafia undercover to rid the city of all its criminal elements. He becomes a one-man army who takes on Ali Bhai and his entire gang, while rooting out the corrupt elements of the police force.