The film is the story of a legendary warrior, It (Rajinikanth), who lives in Kottaipatinam and his son, Rana. Rishikodagan, the Maharaja of Kottaipatinam (Nassar) starts feeling jealous of his trusted army commander, It''s popularity in his kingdom. One day, when It is returning by ship to Kottaipatinam with his army, after buying horses and ammunition, he is attacked by the army from Kalingpuri. It allows the rival army men to return to their kingdom although he could have defeated and killed them. Before going back, the enemy army poisons the food on the ship, after consuming which It''s armymen fall seriously ill. To save the lives of his men, It goes to nearby Kalingpuri with the ailing men and pleads for medical help before Raja Mahendra(Jackie Shroff) of Kalingpuri. Instead of providing medical assistance, the evil Raja Mahendra takes away all the horses and ammunition of It and holds back the sick army men with a promise to cure them and treat them well. When It returns to Kottaipatinam, Maharaja Rishikodagan, jealous as he is, orders his execution, holding him guilty of letting down his army men. Even as inhabitants of Kottaipatinam express unhappiness over Maharaja Rishikodagan''s execution order, he goes ahead and has It killed.
The film begins with It''s younger son, little Rana, leaving Kottaipatinam and reaching Kalingpuri. Not revealing his identity to anybody, he trains as a warrior there and grows up to become a fearless warrior (Rajinikanth). He wins the confidence of Maharaja Mahendra Raj and tricks him into letting him take the armymen of Kottaipatinam, who were being treated as slaves by Mahendra Raj, to fight the Kottaipatinam army. Once he reaches the border, he asks the enslaved armymen, originally belonging to Kottaipatinam, to cross over to Kottaipatinam. Maharaja Mahendra Raj and his son, Veera Mahendra (Aadhi), are livid at being tricked by Rana. Here, in Kottaipatinam, Maharaja Rishikodagan is alarmed at seeing It''s son return with the armymen his father had given to Mahendra Raj and for which he (Rishikodagan) had had him killed. Rana revives his friendship with Rishikodagan''s son, Sengodagan (R. Sarathkumar), his childhood friend. He learns that his mother Yaahavi (Shobana) has since died, his elder brother is missing, and his sister, Yamuna (Rukmini Vijayakumar), is in love with Sengodagan who also loves her very much. Like a true brother, Rana gets his sister married to Sengodagan after making Maharaja Rishikodagan agree to the alliance despite class difference between the two families. However, Maharaja Rishikodagan, angered by having to let his son marry a girl from a family not matching his status, seeks revenge by disowning his son for having married Yamuna. Disgusted with his father, Sengodan walks out on him, taking his newly-wed wife with him. Rana and Maharaja Rishikodagan''s