Ravi (Vijayakumar) is happily married to Savitri (Latha). Savitri's brother Ramesh (Rajinikanth) has come from Singapore, and they all go to Ravi's estate for a vacation. And that night starts Savitri's terrible ordeal. An apparition is visible only to her eye; an eerie song and the sound of anklets make themselves heard only to her ears. And before she realizes what is happening, another spirit enters her body, driving out her own spirit!

Overnight Savitri's persona itself changes; she talks, walks and behaves like a different woman. Ramesh is puzzled at the change, and keeps a watch on her. He follows her, as she wanders all over the hills with the easy familiarity of a person who has lived there all her life. He sees her shed tears over two names carved on a tree trunk; the fading legends "Radha" and "Ravi" tell the tragic tale of love and loss. He follows her as he goes to a humble cottage and eavesdrops as she introduces herself to the incredulous old woman (Pushpalatha) as her dead daughter Radha. It was only due to her unrequited love that she was hovering as a banshee so far, she explains. She tells excitedly that in the 5 days before new moon, if she can have a physical union with Ravi even once, she would be alive again. And if she didn't succeed? Well, she would push Ravi down the same waterfall where she had met her end, so that they could unite in the other world.

In the old disused bungalow of Ravi, Ramesh sees a picture of Radha and listens to a cassette as well. He confronts Ravi with the photo, and Ravi tells all- how he fell in love with Radha (Padmapriya), the daughter of the late factory supervisor. They roamed all over the hills, even as the lofty knolls were passive spectators to their love. With steadfast determination, Ravi manages to get his father's (V. S. Raghavan) acceptance. But when he rushes back with the happy tidings, he finds only her body- she had met a watery grave trying to escape from the clutches of her evil suitor Ranga (Kannan). Armed with the facts now, Ramesh thwarts off the attempts of the possessed Savitri's attempts to sleep with Ravi.

The first night she dresses provocatively and sings a song of seduction in the bedroom. Ramesh knocks the door and pulls Ravi out telling him that there was a call that the factory is on fire. And the second night, he dissolves some strong sedatives in Ravi's glass of milk. The third morning, in the labour day gathering where they are special invitees, the transformed Savitri dances and sings with abandon. That night, she takes Ravi to their summer cottage, but her plan goes awry again when Ramesh sets it on fire.

On the next night, Ravi is returning home when Ranga waylays him to settle old scores and hits him on the head. Ramesh rescues him in time. Of course, that night too passes without Radha's schemes seeing success. The last night, its do or die for Radha, and so she puts the vigilant Ramesh to sleep and lures Ravi out with a soft song of invitation. Savitri's displaced spirit crying out ‘Anna! Anna!’ and the barking dog wake up Ramesh and soon he is in pursuit as Radha sings and leads Ravi up the hill. In the end, good triumphs over evil.