Udambu Eppadi Irukku is a remake of Telugu Movie Evadaithe Nakenti. Rajasekhar is Army major and comes to Chennai on two months leave. His father Raghuvaran is a corrupt minister and would do anything to become the chief minister. Raghuvaran’s two sons-in-law are IAS and IPS, they too are corrupt and in fact encourage and support their father-in-law in all his deeds. Like any other film, here too Rajasekhar has got a loving sister and an innocent mother who hold up to him.
Rajasekhar doesn’t like his father and brothers-in-law activities and he goes his way of helping people and fighting against the injustice. This leads to a tiff between father and son, and they start hating each other. Meanwhile our hero’s loving sister is in love with a common boy at the college. Rajasekhar wants them to get married while his father has already fixed her alliance with a police officer. To avoid her love affair, Raghuvaran and his two sons-in-law get the boy killed and his sister is married off to the police officer.