Ullam Ketkumae movie is all about a group of five college friends - Shaam (Shaam), Imman (Arya), Pooja (Laila), Priya (Asin) and Irene (Pooja). The friends gather for the wedding of Imman.
There begins the movie with a flashback, all recollecting their college days. In college, they spend all their time together.
Imman, a popular cricket player in the college falls in love with Irene, an Anglo-Indian. So does Shaam with Priya. However, Pooja, the geekish tomboy develops a soft corner for Shaam. When they go for a college culturals, each one tries to convey his love for the other. However Priya refuses to accept Shaam's love while Pooja, coming to know of Shaam's interest in Priya, conceals her desire.
When Imman gets dropped from the college cricket squad, Irene picks up a fight with him and breaks up, resulting in the former attempting a suicide. He later resolves to fight his way back in the team. And then on life takes over. After several years, they all gather for Imman's wedding arranged with his relative. In the meanwhile, he rises to become a popular cricketer representing the country.
All friends who gather for the wedding recall their early days. Enters Pooja, who has settled down in USA. The rest is all about Pooja and Shaam meeting each other again and falling in love.