Kundavi (Jyothika) was brought up in a small village called Ambasamudram. She has two school friends but one day both get married and leave. Kundavi's father then arranges her marriage to Goutham (Surya Sivakumar). Both look gloomy during the wedding.
Six years later in Bombay they have a 5-year-old daughter Aishu (Shriya Sharma) and live as a happily married couple. Goutham works as an automobile chief engineer and goes to New York for a short period. During this time, Kundavi comes across Goutham's old college diary. In college, he was attracted to Ishu (Bhumika Chawla), a local MP's daughter. Gautham and Ishu fall deeply in love and they decide to get married. At the registrar's office after Gautham ties the thali, Ishu's father and his men beat him up. At the end of the diary, Goutham writes a note: "if I have one wish, it would be to live with Ishu happily at least for one day."
Goutham comes back from New York and finds his wife changed. She works late and avoids him. She finds Gautham's lost love Aishu. Ishu has changed to a Western-clad modern girl in contrast to the salwar kameez she wore in college. Kundavi asks Aishu to visit them and she tells her husband that he should live happily with Aishu for a day and that for that one day, she and their daughter do not exist for him, and then she leaves.
Kundavi returns home at the end of the day and finds Aishu's letter: "Dear Kundavi, You gave me one whole day with your husband, but all we needed was an hour; 40 minutes of silence, 10 minutes of formal inquiries, and 10 minutes to talk. Even in those 10 minutes all he talked about was you and how you completed him. Now I see how well you've merged in his life and I dont want to disturb your happy life as I see how you two are immensely in love. Gautham is yours for this birth but he will be mine for the next 6 births. I have always loved Gautham, and I will love him in my next birth too. But not as Ishu, but as Kundavi."
Thus the story ends with the happy reunion of Gautham and Kundavi Awards
Tamil Nadu State Film Awards
• Best Female Playback - Shreya Ghoshal 2007 Filmfare Awards South
• Best Music Director – A. R. Rahman
• Best Playback Singer (Female): Shreya Ghoshal for the song "Munbe Vaa…"