Rusi Kanda Poonai is a gripping emotional story of Savithri and Ramesh, played by Saritha and Sudhakar respectively.

Saritha and Sudhakar love each other and Ramesh promises her that he will marry Saritha. but later it is revealed that Sudhakar has already married and dejected, Saritha leaves the hostel run by Manorama and her Siddha expert husband Suruli Rajan, for her hometown. In fact, Sudhakar's marital life was a disaster as they often have quarrels. Eager to meet Saritha, Sudhakar comes to the hostel, but she has already left. Saritha becomes pregnant and delivers a baby girl and meanwhile, Sudhakar's wife, Y. Vijaya dies in an accident. Saritha was never informed about the delivery of her baby girl and her mother gives the child to the greedy couple M. R. R. Vasu and Ganthimathi and both always torture the girl, also blackmail Saritha's mother for money to hide the truth of Saritha's daughter's birth. Saritha gets married and have a happy life blessed with a daughter. Meanwhile, Sudhakar is in search of Saritha and one day meets her at beach as her daughter gets almost drowned, but saved by him. Saritha avoids speaking with Sudhakar. Meanwhile, M. R. Radha blackmails Saritha's mother for money and unable to handle the pressure, she dies revealing the truth to Saritha's daughter. What will happen to Sudhakar, will Saritha's husband finds out the truth and what happens to M. R. Radha gets revealed in the climax.