The story is set in the backdrop of the slums of Pudhupettai in Chennai, where a high school kid Kokki Kumar (Dhanush) sees his mother dead after he comes back from watching a film. He realizes that his father, the murderer, is also planning to kill Kumar. Sensing danger, Kumar runs away from home. Homeless and with no food, he resorts to begging until he is falsely arrested while standing by and watching a commotion on the street. In jail, he befriends henchmen of a local goon Anbu, who works for the opposition party's leader Thamizhselvan(Azhagam Perumal). They take Kumar with them and give him petty jobs. In a confrontation with gangsters headed by the ruling party's politician Murthy, Kumar kills Murthy's brother, thus earning the respect of his gang. Krishnaveni (Sneha (actress)) is a prostitute who works under Anbu. Kumar falls in love with her and asks Anbu to release her. Anbu is shocked at Kumar's audacity and refuses his request. He also thrashes Krishnaveni and orders his men to kill Kumar. Kumar approaches Anbu and begs pardon but Anbu is not ready to make peace. Kumar is infuriated and kills Anbu and asks help from Thamizhselvan to keep him safe. Thamizhselvan says if he could escape until the next day morning from Anbu's men, he would be allowed to take over Anbu's money extortion, rowdyism and brothel business in the area. Kumar somehow survives and Thamizhselvan replaces Kumar in Anbu's position.