Illalu is the movie which reflects the fact about the original identity of a married women's life.Kiran (Shoban Babu) and Kalpana (Jayasudha) are married and they even have a son.Kalpana is a very irresponsible and care-free woman who thinks that her husband and her son are a big obstacle for her happy life.She wants to enjoy her life with lots of money, without having responsibilities.So she leaves her son and husband and marries an old man for money.In the meanwhile, Kiran meets Jyoti (Sridevi) and they both get married.Jyoti also accepts Kiran's son.But unexpectedly they meet Kalpana who has now understood her fault and wants her son back.What will Kiran do in this situation? To which mother will he give justice, forms the rest of the story.