The story is set in the backdrop of the slums of Pudhupettai in Chennai, as the title suggests, where a high school kid Kokki Kumar (Dhanush) sees his mom dead after he comes back from watching a movie. His father, the murderer is also planning to kill his son Kumar. Kumar sensing danger runs away from home. Homeless and with no food Kumar resorts to begging until he is falsely arrested while standing by and watching a commotion on the street. In jail he befriends handymen of a local goon who take Kumar with them and give him petty jobs to do. In a confrontation with goons of another gang Kumar kills the brother of his enemy gang's head Moorthi thus earning the respect of his gang and making enemies for himself both within his gang and outside.