Kamal Haasan, Jayaram, Devayani, Jyothika
A. R. Rahman
Thenali (Kamal Hassan) is a Sri Lankan Tamil who has come to Chennai for psychiatric treatment because of numerous phobias caused by his trauma of the Sri Lankan Civil War. Panchabhootham (Delhi Ganesh) and his assistant (Ramesh Khanna), who are the doctors treating Thenali, are jealous of a relatively junior doctor Kailash (Jayaram) getting all the media attention. They send Thenali over to him, believing that his failure to cure Thenali of his phobias will derail his success. Soon after their first appointment, Kailash heads to his home in Kodaikanal on a vacation with his wife Jalaja (Devayani) and his two children. Kailash tells Thenali to wait until after the vacation before his therapy can begin, but Panchabhootham asks for Thenali to go meet Kailash while on vacation.
The expected happens. Thenali falls in love with Janaki (Jyothika), the younger sister of Kailash, which is vehemently opposed by the latter. The whole film is about how Kailash goes mad with the antics of Thenali and even begins to suspect that his wife has an affair with Thenali, as she has a soft corner for the latter. He even tries to kill Thenali by tying him to a tree with a time bomb. Thenali, thinking it is a fake bomb used only to relieve him from his fears, removes it and puts it in Kailash's house, causing it to explode. Seeing this, Kailash suffers a paralytic attack. Thenali later marries Janaki.
While Thenali, Kailash and family are at a picnic, Thenali's long-lost wife shows up and re-unites with him. Enraged, Kailash jumps out of his wheelchair and berates Thenali for ruining Janaki's life, but soon realises this was all a set-up by Thenali to cure Kailash's paralysis through shock treatment, which succeeded; the woman was actually actress Meena, who Thenali hired to pose as his wife.