Sivagiri is a bladesmith in a remote village near Thirupaachi. He has a lovable sister named Karpagam. He runs into some hilarious incidents while searching locally for a groom for his sister. Sivagiri confides to his friend Kannapan that he wants his sister to be in a good city after her marriage. Sivagiri also nods his acceptance when a city guy proposes to Karpagam. He accompanies the newlyweds to Chennai and finds a girl named Subha welcoming them, and they both fall in love after initial mishaps.

On a trip to Chennai, Sivagiri rescues a court witness from Pattasu Balu, a don dominating central Chennai. He also learns of a local don Pan Parag Ravi, who controls North Chennai and troubles Karpagam's husband's canteen business. In an altercation in a cinema theater, Kannappan gets murdered by a thug Saniyan Sagadai, who dominates South Chennai. Karpagam's husband told Sivagiri to leave Chennai if he wants his sister to be happy. After Kannapan's funeral, he leaves his hometown, stating that he got a job in a cloth manufacturing company. In reality, he comes with a mission in Chennai.

Sivagiri warns Sagadai, stating that the latter will be killed by him. He also calls ACP Raj Guru and warns him that he will kill all the dons of Chennai, as the police department fails in their duty. Later on, Sivagiri's friend Veluchamy who is a police inspector, learns of this. Sivagiri challenges Veluchamy that he will give up his mission if the latter keeps any one thug of Chennai in jail at least for a single day. Veluchamy fails in his mission and loses his son, as he was killed by Balu.

This harsh lesson makes Veluchamy help Sivagiri. Thus, Veluchamy lists Sivagiri the entire mafia network of Chennai by providing the specification of who leads the various areas. Sivagiri writes their names in papers and randomly chooses Balu. He kills Balu, stating that he is not killing instead 'clearing'. One day, Subha meets Sivagiri in a temple and finds that he is not working in any cloth manufacturing company. Sivagiri manages to make Subha believe that he is working in a travels company. Thus, Subha gets a promise from Sivagiri that he should meet her and spend time with her frequently.

Later on, Sivagiri provokes Ravi to kill his own brother by sticking funeral posters of Ravi and making him think that his brother is the person who is killing people all over Chennai. After the death of Ravi's brother, Ravi realizes his brother is not the one who stuck the funeral posters, so he hides himself in a politician's house to be away and safe from the hands of Sivagiri. The politician damages his car and house and makes the policebelieve that someone has attacked his house. The police decides to provide security for the politician. This makes Ravi feel happy, considering that Sivagiri can't come to his place by fooling all these inspectors and kill him. Veluchamy soon found out that Ravi is hiding in the politician's place.

Sivagiri wants Veluchamy to disband the police protection, but Veluchamy refused because that is the police's responsibilities to protect. He can only inform Sivagiri, who has to kill Ravi. Later on, Sivagiri brings a group of people who rally due losing their money to a fraud financier who is hiding in the politician's place. With the rally, Sivagiri enters Ravi's fort and kills him. Raj inquires the people who were involved in the rally regarding identity of Sivagiri. However, nobody wants to tell anything because they think Sivagiri is doing the police's job while the police do nothing and wait for their salary. Raj's daughter is willing to die than reveal Sivagiri's identity because she was rescued by Sivagiri from Balu.

Later on, Sivagiri decides to kill Sagadai, and warns him. This makes Sagadai seek the protection of a mass group of thugs from Chennai. Sivagiri uses this as a chance to destroy the entire mafia gang of Chennai. He ignites a war between the police group and mafia gang in a very diplomatic manner. Sivagiri disguises himself as a police inspector and enters Sagadai's fort. Veluchamy helps Sivagiri in his mission by hurting himself. Raj orders his squad to hit the thugs.

Sivagiri enters the house in a police uniform, confronts a thug, and forces him to wear a police uniform. After that, Sivagiri shoots and kills the thug and throws him out of the window. Thinking that one of his fellow officers is dead, Raj orders for open fire. All the thugs were killed, but when they checked the dead 'police officer', they realize Sivagiri's trick and run upstairs to find him. However, Sivagiri already stabbed Sagadai (taking revenge for his friend Kannapan's death) and threw him to the ground right before the birth of a new year. Subha welcomes Sivagiri, Karpagam, and her husband once again after returning home. Sivagiri gives Subha the necklace that he is wearing, and they unite at the end.