Sillunu Oru Kaadhal Full Story Explained (2006)

Sillunu Oru Kaadhal begins in a small town called Ambasamudram in Tamil Nadu. Kundavi lives there with her family. She and her two friends want to have love marriages. But Kundavi fails to find a partner on her own. Her father arranges her marriage to Gowtham, a man she does not know. Both look unhappy on their wedding day. They marry without love or choice.

Fast forward six years. Gowtham and Kundavi now live in Mumbai. They have a five-year-old daughter named Ishwarya, whom they call Ishu. Gowtham works as a chief mechanical engineer at Maruti Suzuki. Kundavi works at a local call centre. They are deeply in love and live happily as a married couple. Gowtham goes to New York City for a short work trip. While he is away, Kundavi finds his old college diary.

She starts reading the diary out of curiosity. The diary reveals Gowtham's past. He wanted to be an engineer from a young age. He forced his uncle to pay for a seat in Coimbatore for mechanical engineering. By his second year, he became powerful and feared in college. He fell in love with Ishwarya, whose father is a Member of Parliament from Coimbatore. They fell in love and decided to get married. But at the registrar's office, Ishwarya's father and his men beat up Gowtham. They separated the lovers and sent Ishwarya to Sydney, Australia. At the end of the diary, Gowtham writes: 'If I have one wish, it would be to live with Ishwarya happily at least for one day.' Later, his uncle's dying wish forced him to marry Kundavi.

Kundavi is heartbroken after reading the diary. She feels betrayed and insecure. When Gowtham returns from New York, she acts cold and distant. She works late and avoids him. Gowtham notices the change and feels confused. One day, Kundavi realises how much Gowtham loves her and missed her during his trip. She decides to find Ishwarya, who has just returned from Australia. Ishwarya has become a modern girl and ignores her father at the airport. Kundavi invites Ishwarya to their home.

Kundavi tells Gowtham that he can spend one day with Ishwarya. She says that for that one day, she and their daughter do not exist. She leaves them alone. Gowtham and Ishwarya spend the day together. They visit old places and remember their college days. They share their love and how they missed each other for six years. They fall in love again and get intimate. But then it is revealed that this was all Kundavi's dream.

Kundavi wakes up panicked. She rushes to check on Gowtham and Ishwarya. She finds Gowtham alone at home. She asks where Ishwarya is. He gives her a letter. In the letter, Ishwarya says that Kundavi gave them a day, but one hour was enough. In that hour, forty minutes were silence, ten minutes were formal questions, and ten minutes were talking. In those ten minutes, Gowtham only said Kundavi's name. Ishwarya realises that Gowtham truly loves his wife. She says she wants to love Gowtham in her next life, but as Kundavi, not as herself. She wishes them happiness and leaves forever.

Gowtham confesses that he hid his past to protect Kundavi from getting hurt. He never wanted to share his love. Kundavi says she brought Ishwarya to make him happy. They cry and hug each other. Their daughter Ishu joins them. Diwali fireworks burst in the sky. The film ends with the family united and stronger than ever.