Sundaravadivelu is a rich but sadistic villager. He is also the manager of the local school, and manages it authoritatively without respecting anyone; he siphons the school's money for his own wants. Sundaravadivelu lives with his chronically ill wife Lakshmi and their two children: son Raja and daughter Bhavani. Lakshmi's father Thambusamy, a pensioner, lives in the same village with his second daughter Shenbagam. Sundaravadivelu, who has lent money to Thambusamy, keeps demanding it back and also insults him on several occasions. Shenbagam falls in love with Prakash, a new teacher in the school. Sundaravadivelu does not approve of their relationship as he wants to marry Shenbagam, citing Lakshmi's chronic illness. He puts the proposal before his father-in-law and offers to write off his debt if he agrees. However, Thambusamy does not agree and Sundaravadivelu vents his anger on his wife.

Bhavani falls sick, and Lakshmi takes her to the recently appointed village health inspector. When they meet, they realise that they had been neighbours some years back and had met when he had come to meet her father to seek her hand in marriage. By then, Lakshmi was already engaged to Sundaravadivelu, hence the health inspector left in disappointment. Recollecting this, he tries to help her. When Thambusamy, unable to tolerate the harassment of his son-in-law, plans to leave the village, the health inspector offers money to settle the loan. When Sundaravadivelu learns this, he alleges an extramarital affair between his wife and the health inspector. With the help of the village panchayat, he throws Lakshmi out of his house, keeping the children with himself. The health inspector leaves the village to avoid causing further strain in Lakshmi's life, while Lakshmi goes to her father's place. Unable to withstand separation from her children, she dies.

Sundaravadivelu marries another woman and neglects his children, who keep visiting Shenbagam for food and care. Prakash meets Thambusamy and proposes to marry Shenbagam; Thambusamy readily accepts, and the marriage is fixed. Prakash tells Sundaravadivelu that the school's management has learnt about his mismanagement and has decided to take action against him. Shenbagam visits Sundaravadivelu to seek custody of his children so she can take care of them. Sundaravadivelu, who is jealous of her new status and enraged that she rejected his marriage proposal, degrades her modesty by undressing her forcibly and proudly declares that he is the first person to see her nude; he further taunts Shenbagam by saying that whenever her husband sees her, she would be reminded of this incident. Sundaravadivelu's wife witnesses this and disowns him. The villagers too learn of this; angered, they corner Sundaravadivelu, take him to the river and ask him to choose his way of death. Sundaravadivelu, remorseful over turning the peaceful villagers into a vengeful mob, shares a tender moment with his children, then drowns himself in the river.