Arumpon is a village youth from
Tirupathur who has a beloved step-sister Thulasi. Arumpon holds a
puberty showering function for his sister despite hesitance from his maternal uncles, who disregard Thulasi for unknown reasons. Even his paternal uncles disregard Arumpon's family and consider Thulasi as a curse on their family. The only people who care for Arumpon's family are his grandfather, Arunmozhivarman, and his cousin, Paramu. Arumpon develops an affection with his maternal cousin Maangani, despite her father's disapproval. Arumpon actively looks for an alliance with his sister because his maternal uncle disapproves of Thulasi being married to their sons. Despite Arumpon finding a prospective groom for his sister, his paternal uncle foils it, and Thulasi's engagement is called off. Arumpon and Paramu have a running feud with Ayyanar, a ruffian and his uncle since they closed Ayyanar's liquor shop and stopped them from selling agricultural land via a court order. So, Ayyanar decides to marry Thulasi for retribution. Arumpon reluctantly agrees to the marriage on his mother's and Thulasi's insistence. It is revealed that Thulasi is Arumpon's adopted sister who was the daughter of Dharma, a close friend of Arumpon's late father Chandrabose, who adopted Thulasi after Dharma's death. Chandrabose later got killed after failing to save Esakki, Thulasi's biological brother, from getting electrocuted due to a faulty wire caused by Chandrabose's enemies. Ayyanar tries to insult Arumpon at every turn, but Arumpon takes it with a light heart since he is his brother-in-law. Thulasi was falsely arrested for Ayyanar's illegal liquor hoarding. When confronted by Thulasi, Ayyanar hits her. Arumpon mercilessly thrashes Ayyanar for retribution. Following this incident, Ayyanar's close friend Paari comes with men to seek him and go after Arumpon for retribution. In a heated exchange, Paari insults Ayyanar for getting beaten up by his brother-in-law and in a drunken stupor, Ayyanar kills Paari accidentally. After realising what has transpired, Paari's men attempt to kill Ayyanar. Ayyanar escapes from them but is not closely trailed by men out for blood. No one comes for Ayyanar's rescue even his maternal uncle, but Arumpon and Thulasi manage to rescue him and hand him over to the police. Enraged by this, they seek to kill Arumpon too. To end this problem without bloodshed, Arumpon, his mother, and his sister surrender to the
panchayat of Paari's village. He explains that he knows the suffering of growing up without a father and wants to end this without further loss of life. Even though he can beat up every goon there and escape, he does not wish to do so. He offers to marry Paari's widowed wife, but she compliments Arumpon's good nature and not wanting to make Thulasi a widow agrees to end this peacefully. During the film's
closing credits, it is intended that Arumpon, Thulasi, and his mother have reconciled with the rest of the extended family. Ayyanar has been released on parole to attend Thulasi's
seemantham (Baby shower) and it is revealed that he made peace with Arumpon. The film ends comically with Arumpon breaking the fourth wall mimicking his grandfather. == Cast ==