Sivappu Sooriyan is one man's hunt for his missing family and to bring to book the perpetrators of their ruin.

Vijay (Rajnikanth), a merchant navy officer, comes home on leave to meet his sister Selvi (Saritha) and her husband Vishwanthan (Delhi Ganesh) but finds them missing. In his search for them, he bumps into Chitra (Radha) who falls in love with him. With Chitra's help, Vijay is able to find Selvi, but is shocked when he learns that her husband has vanished and she has stopped speaking. Unable to make Selvi speak but determined to resolve her troubles, Vijay with the help of his friend Vidyasagar (Y.G. Mahendran) discovers that Vishwanathan had testified in court against a dangerous criminal and is being held hostage by his associates. Vijay decides to disguise himself as a smuggler and gets into the underworld. Whether he is able to retrieve Vishwanathan and bring normalcy to Selvi's life forms the rest of the story.