Ranganayak, a rich women, has three sons : Gopi, Madhu and Balu. Ranganayaki wants absolutely a grandson and she will pass on her whole inheritance to her son who has a male child. The elder sons have only daughters and Balu is still bachelor. Balu is a singer in the marriage functions and he falls in love with Swathi, a girl from a middle-class family. He gets married with her and Swathi becomes pregnant. Balu's best friend, Raja, an honest journalist, is married to Shanthi and his wife is also pregnant. Swathi and Shanthi deliver the same day. Balu has a daughter although Raja has a son. In the meantime, Ranganayaki has a severe heart attack and the doctor says to not reveal shock news. In the hospital, a misunderstanding happens and Balu's father shows Raja's son to Ranganayaki in a serious condition. Ranganayaki is immediately recovered. Balu maintains the lie to save his mother's life. What transpires next forms the rest of the story.