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.
Vaidyalingam Moopanar and his younger brother Sundaralingam live together along with their family. It is one big happy joint family. Vaidyalingam does not have any children while Sundaralingam has two sons. His older son's left hand is paralysed since childhood, while his younger son is studying in college in the city. Vaidyalingam's wife is bitter and keeps cursing Sundaralingam and his family, while Vaidyalingam is very affectionate towards them and is unhappy with his wife for her bad behaviour. Arrive Singaram and his sister Amudha who are related to Vaidyalingam's wife Akilandam. Singaram's entry into the house causes a lot of confusion and the family splits. Sundaralingam's younger son Mani gets married to Amudha. Evil Singaram misleads Akilandam and Mani into giving him money due to which both Akilandam and Mani get into trouble.