Manoranjitham or Mano (Vinodhini) leaves home writing a suicide note to her parents. Shenbagam (Mounica) is in love with her neighbour, Shivasubramaniam, or Shiva (Prashanth) from childhood and wants to marry him. However, Shiva does not reciprocate her love. He is a nature lover and spends all his days in the forest. Mano who has come to the same forest to die notices Shiva and finds his activities interesting and intriguing. Shiva meets her and stops her from committing suicide. However, she refuses to return to the town stating that she ran away from home as her parents were planning to get her married to someone she does not like. He stays with her that night for her safety. Next day, he goes home, takes some money and clothes, and returns to the forest to be with Mano. Soon they both fall in love and spend time together happily in the forest.
Shiva's friend Azhagiri (Vijay) comes home to stay with Shiva for a few days. Shiva also returns and tells Azhagiri about his love for Mano. Azhagiri is concerned as he has noticed Shenbagam's love for Shiva and her refusal to marry anybody else as from childhood she has decided that Shiva is her husband.
In the forest, a thug sees Mano bathing and tries to molest her. By then Shiva arrives and saves her. Mano now agrees to come to his house. He makes her stay in his room at the rooftop with the help of Azhagiri. He hides her from everyone but one-day Shenbagam sees Mano in his room and informs his grandmother. However, by the time they come, Shiva manages to hide her.
Azhagiri advises Shiva to get married to Mano and Shiva goes to make arrangements. Mano comes to know about this and is upset that Shiva has planned the marriage without getting her consent. On Azhagiri's insistence on why she is refusing to marry, she confesses that she has a peculiar disease and will die soon unless she is operated upon. Her parents were trying to get the operation done by selling the family's only house. To save her parents from further difficulty, she ran away from home to commit suicide and gave a different reason to Shiva to hide this truth. Shiva returns and both Azhagiri and Mano are confused about how to stop him from his marriage plan. The next day morning Mano goes missing. Both Shiva and Azhagiri go searching for her but do not find her anywhere.
They notice an advertisement issued by Mano's father Thanikachalam (Veeraraghavan) in a newspaper with an address. They go there and see her admitted in a hospital in a serious condition. Mano is happy to see him and expresses her deep love for him and her dream to live a long life with him and dies. Shiva is shocked to see her dying in his hand. Shiva returns home with sadness. Shenbagam notices and rushes to his room and gives him the emotional comfort and Shiva accepts her.
[from the book Pride of Tamil Cinema: 1931 to 2013, by G Dhananjayan, Blue Ocean Publishers, 2014]