Karthi, Catherine Tresa
Kaali (Karthi) is an impulsive and short tempered middle class guy who works in a corporate company and enjoys playing football during his spare time. His best friend is Anbu (Kalaiyarasan), who is a young political aspirant. They along with their gang live in the dilapidated flats of the housing board in Vyasarpadi. In a long standing bloody feud, two factions of a political party have been laying claim to a wall on which they can paint the portraits of their respective political leaders. Anbu, under the local leader of one of the opposing parties, Maari (Vinod), is determined to claim that wall for their own party. The two parties and their supporters get into frequent clashes and scrapes. In the meantime, Kaali falls in love with Kalaiarasi (Catherine Tresa) and she too reciprocates his feelings.
In a spur of motivation due to the upcoming elections, Anbu reserves the said wall for their party. Although the wall is in their area and technically theirs, the opposition ask Maari's party to give it up as the portrait of their patriarch had been there for quite some time. Moreover, since three deaths had previously taken place in connection to the wall, along with the deaths of members from both parties, people have started to consider the wall a bad omen. Anbu, bolstered by Kaali, however, declines. The opposing party members plan to assassinate both Kaali and Anbu. When henchmen are sent forth to kill Anbu and Kaali, they somehow escape and hide behind a van. They see the son of the leader of the opposing party, who doesn't notice them. In a fit of rage, Kaali kills him. Anbu and Kaali are told by Maari to surrender at the court to avoid being killed by the henchmen. Also, the FIR report filed against them contains only Anbu's name. Anbu takes responsibility of the murder, despite Kaali being against it, and hopes to be released soon. However, just outside the court, some henchmen hack Anbu to death and injure Kaali seriously. Kaali goes into a depression and swears revenge, but is advised against violence by Kalaiarasi, his parents as well as Maari. Kalaiarasi comforts him and brings his life back to normalcy and they get engaged. Maari promises Kaali that they will avenge Anbu.
One day when Kaali and Kalaiarasi are at a restaurant, he notices one of the henchmen of Maari sitting at the next table. When he goes up to him to talk, he runs away in fear. Surprised, Kaali chases him. It is revealed that Maari has joined hands with the opposing party for political gain and it was he who had Anbu assassinated. Kalaiarasi, though reluctant to let Kaali pursue his revenge, lets him go. At a local meeting where Maari is being felicitated, Kaali spills the beans about Maari and the locals chase Maari out. In a final act, Kaali splashes paint on the wall thus ruining the portrait. Soon everyone follows suit. Maari plots to kill Kaali. However, Maari is betrayed by the touted successor of the opposing party when he tries to kill Kaali. Kaali, in a final fight sequence, subdues the henchmen sent to kill him and grievously injures Maari, who is soon killed.
Kaali and Kalaiarasi start teaching in the building whose wall was the cause of this blood feud. The wall now has a theme of children's education painted on it. Both the parties still wait to claim the wall soon.in the uncut version it is shown that kaali later goe to anbu's wife's house and tells that he killed anbu for money and suicides.