The movie begins at Pachai Theevu, ruled by a mighty king (Narasimha Raju). His son and prince Jagathalapradhapan (Raja) is a valourous youth who sets out on a mission to capture pirates in the sea. He lands at Sangu Theevu, where the head of the sea pirates Alai Kallan lives. Jagathalapradhapan comes across Mohini (Namitha), who belong to the local fishermen community in the island. Romance blossom between them. Jagathalapradhapan manages to nab Alai Kallan and decides to return to his country. He promises Mohini that he would bring his parents to arrange for their wedding. However the King and his wife Mangayarkarasi (Yuvarani) arranges for their son's marriage with a princess Azhagu Nachiyar (Nila). Jagathalapradhapan tries hard to convince his parents that he would marry only Mohini.