Rajalingam "Raju" is the son of a wealthy Madurai-based industrialist, Sankaralingam, and lives with his loyal driver and friend, Sundaram, at the family estate. Their vacation in the hill station of Kodaikanal brings a quiet backdrop for a growing connection between Raju and a woman named Parvathi, who is connected to Raju’s world through her father, the estate’s trusted accountant. A physician by trade, Gopal also crosses paths with Parvathi and is soon drawn to her, but he keeps his feelings private out of loyalty to Raju.
As Parvathi returns those feelings, Gopal steps back from his own longing to protect the bond between Raju and Parvathi. The couple chooses to marry in secret, with the help of Gopal and the consent of Parvathi’s father. They begin a life together in Kodaikanal, keeping their marriage hidden from Sankaralingam. The happiness is short-lived. Parvathi becomes pregnant three months later, a fact that intensifies the tension around Raju’s union and status.
Sankaralingam arrives at the estate in a rage once he learns of Raju’s marriage and orders his henchmen to turn the estate into a trap, threatening Parvathi and her father. Raju and Gopal race to their aid, but they are thwarted by the older man’s men and forced to abandon Parvathi, leaving her and her father believed dead. The aftermath pushes Raju into an arranged marriage with his cousin Vimala, and soon after, Sankaralingam entrusts the family business to Raju before he dies. Nineteen years pass, and although Raju and Vimala share affection, they remain childless, and Raju cannot forget Parvathi.
The plot shifts to the present, where Sathyamurthy, a nineteen-year-old young man, struggles to hold a job due to his unwavering honesty. He lives with his uncle Murugan and earns a place in Raju’s household as Sundaram’s new recommendation for a personal servant. When Sathyamurthy shows a photograph of his mother and asks for prayers, a startling truth emerges: Sathyamurthy is the son of Raju and Parvathi. Parvathi had survived the fire and was cared for by Murugan, but she died years later without revealing Raju’s parentage to Sathyamurthy or Murugan.
With the assistance of Gowri, Sundaram’s daughter, Sathyamurthy grows in education and falls in love. Raju, upon learning of their relationship, gives his blessing, while Gopal discovers the truth about Sathyamurthy’s paternity but dies of a heart attack before he can reveal it. Meanwhile, jealousy festers in the household as Rathnam, a scheming servant, and his wife plant Vimala’s diamond necklace in Sathyamurthy’s suitcase, aiming to cast suspicion on him.
When the missing necklace is found, Raju angrily ejects Sathyamurthy from the house, insisting on his innocence. The revelation that Sathyamurthy is Parvathi’s son weighs heavily on Raju. Gowri presents Parvathi’s photograph to Raju, and he is left stunned by the truth of his past. He then discloses the history surrounding Parvathi to Vimala, who comes to accept Sathyamurthy as her own son.
Before the family can be reconciled, a crisis erupts: a fire breaks out in one of the mills where Sathyamurthy works. Feeling deeply wronged, Sathyamurthy contemplates suicide by entering the blazing mill. Raju arrives in time to rescue him and, in the process, reveals the full truth about Sathyamurthy’s birth. The emotional storm finally gives way to a reunited family: Raju and Vimala affirm their love and acceptance, Sathyamurthy weds Gowri, and the household is restored with a shared sense of kinship and renewal.
