Nirangal Marukindrana centres on the family of Ramanathan, a retired pensioner, his wife Parvarthy and the children. Their three sons, often neglecting the parents’ welfare, tend to spoil their own wives and families. Sekar, their youngest son, is a husband who often submits to his wife Lata’s wishes. As the old couple and their daughter, Pushpa, stay with Sekar, misunderstandings and conflicts often arise within the household. Lata often connives with her husband to find ways of getting the old couple and Pushpa to shift out.
One day while reading the papers, Ramanathan discovers that he has won the first prize in a lottery. Suddenly, the attitudes of Sekar and Lata change. Instead of plotting to get them to shift out, they spare no effort in ensuring that the couple and Pushpa continue to stay with them. However, Sekar comes home one day with the announcement that the last two numbers of the first prize have been changed. Immediately, Sekar and Lata again change their attitudes, and ill-treat the couple.
As Ramanathan, Parvarthy and Pushpa prepare to leave the house, Ramanathan reveals to Pushpa that although the ticket number has been changed, the first prize is still won by him as he also has the ticket for the latest number. This is because he had bought ten tickets. Sekar and Lata learn of this, and realise their mistake. They try to persuade the couple to stay with them but will they?