Kandasamy, a restaurant owner, has a son, Muthupandi, and three daughters, Jamuna, Rani, and Meena. Muthupandi had fought with his father when he was young, cut Kandasamy's hand with a knife, and ran away to Mumbai with 2 lakh rupees. Kandasamy marries off Jamuna and [Rani] to distant relatives Ganga and Dhamu, who are jobless and lazy. They spend lavishly and irresponsibly, taking money from the restaurant without Kandasamy's knowledge. Jamuna and [Rani] support their husbands' wrongdoings, unable to confront them.
Kandasamy hires Manickam, a jobless young graduate, to supervise the restaurant. Manickam works sincerely, introducing catering ideas to boost profits. [Ganga] and [Dhamu], envious of Manickam, hire goons to chase him out, but Manickam beats them both. Meena develops feelings for Manickam, impressed by his innocence and bravery. Kandasamy too decides to marry [Meena] to Manickam and asks him to stay with him after marriage. Initially, Manickam refuses, but his mother's persuasion makes him accept. They get married and move into Kandasamy's house.
On the first night of their marriage, co-brothers [Ganga] and [Dhamu] create a ruckus, demanding their rooms back, leading to a fight between Kandasamy and his sons-in-law. Jamuna and [Rani] are impressed by Manickam's behavior, unlike their husbands'. [Ganga] and [Dhamu] start a chit company, selling their scooters for ₹40,000 (equivalent to ₹160,000 or US$1,900 in 2023) and convincing their wives to sell their jewels for another ₹60,000 (equivalent to ₹240,000 or US$2,800 in 2023). They spend the money lavishly, expecting interest from a film producer. However, the producer delays repayment, leaving Ganga and Dhamu bankrupt and unable to repay the public's money. The enraged public attacks Ganga and Dhamu, but Kandasamy and Manickam intervene. Manickam uses his personal savings to repay the debt, but it's insufficient. Kandasamy decides to pawn the jewels, only to learn they've already been sold. In anger, he chases Ganga and Dhamu out of the house.
They seek help from constable Meesai Muruganandam to re-enter the house and claim their share of the property. However, they spot the goons they hired to attack Manickam at the police station and flee. While escaping, Muthupandi, now a rich hotel owner in Mumbai, returns with his family. They brainwash Muthupandi against Manickam, to take over the restaurant and to drive Meena and Manickam out. Muthupandi's wife Sonia Bose Venkat advises him to support Manickam and Meena, but he's too proud to listen.
Ganga and Dhamu humiliate Manickam, lying to Muthupandi that Manickam beat them, leading him to shout at Manickam. Muthupandi emotionally manipulates Kandasamy, threatening to leave if he prioritizes Manickam over him. This sparks an argument between Meena and Kandasamy, revealing his preference for a male heir. Humiliated, Meena and Manickam move out. Manickam gets a loan and opens a restaurant and grocery shop opposite Kandasamy's, at Meena's insistence. Muthupandi brainwashes Kandasamy against Manickam, making him pawn their home for ₹1,000,000. Muthupandi uses the money to transform his father's restaurant into a bar cum club, while Kandasamy has gone on a religious trip. Ganga and Dhamu fight with their wives, leading to Muthupandi slapping Meena. Manickam retaliates by slapping Muthupandi.
Muthupandi's former henchmen blackmail him for 10 lakhs, revealing a murder at his Mumbai club in the past. Ganga and Dhamu bring escort women, but their wives chase them away. Inebriated, Muthupandi reveals his business losses and the murder to Ganga and Dhamu, who humiliate him. Muthupandi threatens and brutally beats Ganga and Dhamu, but Manickam tries to intervene. Meena stops him, citing past humiliations. However, Muthupandi attacks Manickam, who retaliates strongly. The women intervene, stopping the fight.
Kandasamy returns, learning about the club and his daughters' departure. He confronts Muthupandi, leading to an argument, and gets thrown out. Humiliated, Kandasamy attempts suicide, but his daughters and sons-in-law rescue him. Muthupandi's henchmen beat him, taking him hostage for the lump sum. Manickam rushes to save him, and the three sons-in-law, along with hotel workers, fight off the henchmen. Completely reformed, Muthupandi apologizes to Kandasamy and Manickam. Kandasamy also apologizes to Manickam and Meena, and they finally reunite.
