Rajalingam "Raju" is the son of a wealthy Madurai-based industrialist, Sankaralingam. Living with Raju is his driver and friend, Sundaram. While vacationing in his family estate at Kodaikanal with Sundaram and his family doctor, Gopal, Raju falls in love with a woman named Parvathi. Gopal too becomes smitten with Parvathi when he meets her whilst conducting her father's medical treatment. Parvathi, who knows Raju through her father, as he is also an accountant of Raju's family estate, reciprocates Raju's feelings. Gopal decides not to reveal his love for Parvathi to Raju for Raju's sake. Raju and Parvathi marry in secret with the help of Gopal and the consent of Parvathi's father. The couple lives together in Kodaikanal without disclosing the knowledge of their marriage to Raju's father, Sankaralingam.

Three months later, Parvathi becomes pregnant. Sankaralingam, fearing for his son's safety, arrives at Kodaikanal and becomes furious upon finding out Raju's marriage to Parvathi. He orders his henchmen to set the estate on fire with Parvathi and her father inside. Raju and Gopal rush to save Parvathi, but they are stopped by Sankaralingam's henchmen and are forcefully returned to Madurai, leaving Parvathi and her father for dead. A few months after returning to Madurai, Raju is forced to marry his cousin Vimala. After the marriage, Sankaralingam hands over his business affairs to Raju and dies. Nineteen years pass. Despite having mutual affection for each other, Raju and Vimala remain childless and Raju is unable to forget Parvathi.

Sathyamurthy, a nineteen-year-old who lives with his uncle Murugan, is unable to retain any job due to his honest nature. He becomes acquainted with Gopal, with whose recommendation he becomes Raju's personal house servant. When Sathyamurthy displays his mother's photograph at his house to pray for her, it is revealed that Sathyamurthy is the son of Raju and Parvathi. Parvathi had survived the accident, was cared for by Murugan and died a few years after giving birth to Sathyamurthy without divulging the identity of Raju to Sathyamurthy and Murugan. Sathyamurthy improves his reading and writing skills with the help of Sundaram's daughter, Gowri and the two fall in love. When Raju learns of their love, he approves of their marriage. Gopal learns that Sathyamurthy is Raju's son, but dies of a heart attack before revealing it.

Jealous of Sathyamurthy's influence on Raju, another servant Rathnam and his wife hide Vimala's diamond necklace in Sathyamurthy's suitcase in an effort to get rid of him. Vimala, upset at losing her necklace, searches the house for it. When Raju, Sundaram, Gowri, and Sathyamurthy return after attending a conference in Kodaikanal, Vimala, acting on Rathnam's provocation, orders that Sathyamurthy's suitcase is searched. When the necklace is found in it, Raju throws Sathyamurthy out of his house, despite Sathyamurthy proclaiming his innocence. Gowri then shows Parvathi's photograph to Raju, who is shocked to learn that Sathyamurthy is his own son. Raju reveals the truth about Parvathi to Vimala, who also accepts Sathyamurthy as her son. Before Raju and Vimala rush to bring Sathyamurthy back, Raju learns of a fire breaking out in one of his mills. Sathyamurthy, unhappy of being wrongly accused by Raju, attempts suicide by entering the burning mill. Raju saves Sathyamurthy in time and reveals the truth about his birth to him. The family is united and Sathyamurthy marries Gowri.