Dhanush, Taapsee Pannu
G. V. Prakash Kumar
In Madurai, cockfights are common. Pettaikaaran (V. I. S. Jayapalan) and Rathnaswamy (Naren), cops are tough competitors in these games and it is often Pettai who wins because nobody knows his way of maintaining the quality of the birds.
Karuppu (Dhanush) and Durai (Kishore) are also in Pettaikaran's team. Rathnasamy keeps insisting on having one last fight to win and satisfy his old mother’s wish but Pettaikaran declines to have any more fights with him because he feels Rathnasamy has lost faith in his roosters and will be using nefarious methods to win. Rathnasamy keeps insisting and tries to make him accept the challenge through cajoling, threatening, bribing and other vile acts.
Karuppu falls in love with an Anglo-Indian girl Irene (Taapsee) who dislikes him. He does not recognise this initially and keeps following her. One day the residents of Irene's colony confront him and ask Irene to tell who she is in love with – Karuppu or Dinesh (Attakathi Dinesh), another man in the locality. She points her finger at Karuppu and he goes into rapture. She explains later that she had to lie in order to avoid Dinesh who has been bothering her for a long time. Later, Irene too falls in love with Karuppu.
Meanwhile, one of Pettai's associates is killed in a hit and run accident. In a rage Pettai, suspecting Rathnasamy of the murder, Pettai agrees to the rooster fight and it is decided that the loser will get his head tonsured and give up rooster fights. In the crucial fight, Rathnasamy brings high breed roosters from Bangalore. Karuppu asks Pettai to let his rooster fight against Rathnasamy's but Pettai puts his rooster down and says he will choose the competing rooster himself. Karuppu surreptitiously enters the contest before Pettai can choose the rooster because he needs to repay Irene for the loan he took to prepare his rooster for the fight. Pettai doesn't believe in Karuppu and his rooster and announces that Karuppu will not represent Pettai. The 'underdog' however emerges victorious in three consecutive rounds even when the opponent has spiked his rooster to scald the other rooster.
While initially Pettai is happy that Karuppu won, he is overcome with anger and jealousy by the end of the day. His ego is hurt by the fact that Karuppu earns both popularity and money. Karuppu is not aware of the changes in his mentor's mind. Pettaikaran is so jealous of Karuppu that at first he refuses to speak to anyone and then starts scheming. The money from the competition that Karuppu gives to Pettai for safe keeping, that he plans to use to start a business, suddenly goes missing. Pettai also starts spinning stories about his associates and makes everyone suspicious of each other. He incites Karuppu and Durai into pitting their roosters in a fight. Meanwhile Karuppu's mom dies of the shock of losing all the money. Pettaikaran meanwhile poisons all of Durai's roosters making him suspect Karuppu, who is arrested for this. Pettaikaran then lies to Irene that his wife was in an adulterous relationship with Karuppu. Irene's family also pressure her to move to Chennai which pushes her into attempting suicide. Pettakaran meanwhile calls Karuppu to a location near a temple and informs Durai about his whereabouts. When Irene gets better, she calls Karuppu and informs him that Pettai is badmouthing him. So Karuppu, who puts 2 and 2 together, goes to find Pettai to confront him. Pettai kills himself and Karuppu also finds that Pettai was the one who stole his money. Karuppu does not want to reveal the fact to the public that his mentor was the criminal who stole his money and schemed against him, so he flees with Irene to start a new life in another city.