Koottu is a Compus love story. Hari (Richard) and Balu (Aravindan) who are students and buddies in a college. They come from different backgrounds. Balu is a poor guy who earns money for his education by teaching driving and doing freelance photography.
Hari on the other hand is a from a wealthy family but all this does not come into the way of their friendship.
Hari loves Pooja (Sheetal Iyer) and Balu loves Paru (Lena). They enjoy life to the hilt by having fun inside and outside college but one day Balu disappears. He is found missing and Hari takes the initiative to find him.