The story takes place in the Subramaniapuram area of Madurai city. A convict is released from prison in 2008 after serving 28 years and is stabbed right outside the prison gates. The police are baffled at this as the convict had never spoken to anyone in the prison and refused to meet anyone coming to visit him from the outside during his time in prison. They are shocked about the fact that someone had a grudge against him for 28 years to stab him when he stepped outside prison.

The film then moves to 1980 where Azhagar (Jai), Paraman (M. Sasikumar), Kaasi (Ganja Karuppu), Dopa and Dumka, a polio-stricken physically challenged person, are part of a set of close friends, who are unemployed. They pass their time drinking liquor and fooling around on the streets opposite the house of an ex-councilor Somu and his brother Kanugu (Samuthirakani). Apart from them, the family consists of Somu's wife, their three children including Thulasi (Swathi) and Thulasi's other uncle.

The five friends, particularly Paraman and Azhagu, often end up in jail due to frequent fighting. Cops get a call from someone complaining about the friends each time they do something wrong. Every time they are arrested, Kanugu and Somu bail them out immediately. In the meantime, Azhagu and Thulasi develop mutual feelings for each other. Paraman is against his friend developing feelings for a girl and Azhagu, not heeding to his friends' thoughts, throws up quite a few funny scenes.

There are signs of things to come when Somu is not selected in a local temple's committee for a function. Things take a sudden turn just before intermission when Somu is not elected for his party's (Tamil Nadu's ruling party at the time) district chief post and is ridiculed by his wife for being jobless. This leads Kanugu to lock himself up in a lodge and drink all day. He makes sure the friends hear about him and come to visit. He requests them to murder the person who was chosen for district chief of party post ahead of his brother. Azhagu, Paraman and Kaasi hatch a plan and execute the person almost perfectly. The first half ends here with them running away after the murder leaving a cycle behind.

The second half begins with the cops finding out that Paraman and Azhagu have committed the murder with the help of the cycle they left behind. They surrender themselves before the court hoping that Kanagu will bail them out soon. But they come in for a rude shock when they learn through Kaasi that Somu has been selected for the district chief of party post and is avoiding their contact. They come to terms with reality and stay helpless in jail where they befriend a fellow inmate. He learns their situation and bails them out.

The same friend who aided these guys expects a favor from them — kill his brother-in-law for murdering his sister. Accomplishing this task, these guys now look out for killing Kanugu who cheated them. In the meantime, Thulasi and Azhagu continue to meet up. This leads to Azhagar almost getting killed by Kanugu's men. The friends strike back killing those men later in the day. A few days later they end up hurting Thulasi's uncle in their bid to kill Kanugu. To save his life from the clutches of these buddies, Kanugu sets a trap for Azhagar using Thulasi as bait and kills him using his henchmen. Paraman takes revenge for his friend's death by decapitating Kanugu and laying his head at his friend's murder site. Paraman then calls to Kasi and reveals how he killed Kanugu, during which he sees Somu's henchmen rushing behind Kasi. Kasi betrays Paraman and leaves him at the mercy of the henchmen who kill him.

The story shifts back to the present day where it is revealed the person who was stabbed outside the prison walls is Kasi. He lies in the hospital in critical condition and is being interrogated by a policeman. The doctor intervenes and asks him to leave, after which Dumka comes in and reveals that it is Dopa who stabbed him and then proceeds to remove his air supply and kills him after reminding him of his betrayal.