Chandru (Sivaji Ganesan) has a sister (Rajam) who is married to a handsome Ravi (Balaji). But her in-laws insist on a diamond necklace, without which she cannot join her husband. So, Chandru steals a diamond necklace with a locket and then his sister joins her husband. He and his mother (Shanthakumari) move to Madras where he finds a job in a company owned by a wealthy man (Ranga Rao). He falls in love with his daughter (Saroja Devi). One day, the necklace falls down and the locket opens, revealing a photograph of a young man. The husband and the others at home want to know who the person is. She says she has never seen him. But suspecting the worst, she is sent back to her parental home. Meanwhile, Chandru saves his boss from a huge loss and, the boss, in appreciation, gives him a handsome sum. Chandru buys another necklace with that money and the sister goes back to her husband. However, his boss dismisses him later to keep him off his daughter. The brother goes to the police station and surrenders himself for the theft. There’s surprise when he comes to know that the necklace belongs to his sweetheart, and the person in the locket is her brother who died in the war. However, the father denies he ever had a son. How the puzzle is solved forms the rest of the film.