Sivagiri (Joseph Vijay) is a blacksmith in a remote village near Thirupaachi. He has a lovable sister named Karpagam (Mallika). 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 newly weds to Chennai. He finds a girl named Shuba (Trisha Krishnan) welcoming them, and they both fall in love.
On a trip to Chennai, Sivaguru rescues a court witness from Pattasu Balu (Pasupathy), a don dominating central Chennai. He also learns of a local don Panparag Ravi, who controls North Chennai, and who is troubling Karpagam's husband's canteen business. In an altercation in a cinema theater, Kannappan gets murdered by a thug named Saniyan Sagada (Kota Srinivasa Rao), who dominates South Chennai.
Meanwhile, Karpagam becomes pregnant and Sivagiri takes her to his home town. Then, after the funeral of Kannapan,he leaves his home town stating that he got a job in a cloth manufacturing company. But in reality he comes with a mission in Chennai.
Sivagiri writes a complaint letter to a local police inspector stating that prostitution is prevailing in his area. This provokes Saniyan Sagadai henchmen group and thus they come 20 in number to murder Sivagiri. The latter decides to apply some different colors of turmeric sandal powder in face to hide his identity and then kills all twenty of them including an inspector who fails to do justice to his duty. He also seizes a cellphone from one of the henchmen. Then,he warns Saniyan Sagadai stating that the latter too will be killed by him. He also calls the commissioner and warns him that he will kill all the thugs of Chennai as the police department fails in their duty. Later on, Sivagiri's friend Veluchamy who is also an inspector, comes to know about 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 not only fails in his mission but also loses his son as he was killed by Pattasu Balu, the head of the thug who got arrested.
This harsh lesson makes Veluchamy to help Sivagivi. Thus, Veluchamy lists Sivagiri the entire mafia network of Chennai by providing the specification of who leads the various areas. Sivagiri in his mission decides first to kill Pattasu Balu. Thus,he phones and warns Balu. This provokes Balu to abduct the commissioner's daughter and Balu warns the commissioner that his daughter will be killed if the he doesn't arrest Sivagiri.
Sivagiri, after knowing this fact from his inspector-friend Veluchamy, calls Pattasu Balu and warns him by stating a fake point that one of Balu's henchmen has been abducted by him. Fortunately for Sivagiri, one of the henchmen of Balu was missing in his place. Thus Balu decides to send his mafia gang to Sivagiri's place whose address has been found by Balu with the help of the phone number from which Sivagiri called him. Sivagiri disguises himself as an wounded person and says to the mafia gang of Pattusu Balu that he remembers the person who bet him so hard.This makes Pattasu Balu to bring Sivagiri to his fort. Later on,Sivagiri destroys Pattasu balu and his gang. The fight scene plagarizes burly brawl from the matrix reloaded.
Then, one day, Shuba meets Sivagiri in a temple and finds that he is not working in any cloth manufacturing compnay. But still, Sivagiri manages to make Shuba believe that he is working in a travels company. Thus, Shuba gets a promise from Sivagiri that he should meet her and spend time with her quite frequently.
Later on, Sivagiri provokes Panparak Ravi to kill his own brother by sticking the 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 hides himself in a politician's house to be away and safe from the hands of police. That politician damages his own car and house by his henchmen and makes the police to believe that someone has attacked his house. Thus, the police decide 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. Then, Sivagiri's friend inspector Veluchamy finds diplomatically that Ravi is hiding in the politician's place. Later on, Sivagiri states to a group of people, who lost their money to a financier, that the fraud financier is hiding in the politician's place. This makes Sivagiri enter Ravi's fort with a mass gang and later on Ravi gets killed by Sivagiri successfully.
Then, after some time, Sivagiri meets Shuba as per his promise and woos and romances her on a beach.
Later on, Sivagiri decides to kill Saniyan Sagadai and successfully complete his mission. Thus, Sivagiri warns Sagadai in an indirect manner and also states that if Sagadai doesn't give up then he will be murdered him before the birth of the next new year. This makes Sagadai to 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. Thus, Sivagiri ignites a war between the police group and mafia gang in a very diplomatic manner. Sivagiri disguises himself as a police inspector and enters the fort of Sagadai. Veluchamy too helps Sivagiri in his mission. Finally Sivagiri destroys the entire mafia gang of Chennai along with the Chennai police inspectors before the birth of a new year. Then, Sivagiri surrenders in police and later on he gets released after 6 months. Shuba welcomes Sivagiri, his sister and his sister's husband once again after returning home. At the end, Shuba romances with Sivagiri.
The film ran for over 235 days and was declared a super hit. The film ran for 100 days in Kerala.
