Kuch Kuch Hota Hai, is the story of Rahul (Shah Rukh Khan) and Anjali (Kajol). Both of them students at St. Xaviers College. Anjali being a tomboy gets along very well with Rahul and the other boys. Rahul and Anjali are also the best of friends. Being so close to each other, Rahul and Anjali would probably have fallen in love, however they were too busy enjoying themselves being best buddies! And then Tina (Rani Mukherji) the Principals daughter came into their lives. For Anjali, Tina was a third member of their gang, however, for Rahul, his life was never the same after meeting her. He fell in love with Tina.
Anjali was finally beginning to fall in love with Rahul, and when she finally does manage to sum up the courage to tell Rahul about her feelings, Rahul tells her in his usual friendly manner, that he is falling in love with Tina. Totally oblivious to him, he broke her heart. Broken hearted Anjali decides to leave the college mid-term making up an excuse. It is at this point that Tinas suspicions come true.
The film is shot in the way of a narration being made to Little Anjali, Rahul and Tinas eight year old daughter through the letters her mother left behind for her. Tina tells her daughter to fulfill her dream of bringing back her father and Anjali together - two best friends who would have eventually fallen in love.
Kuch Kuch Hota Hai is the story of best friends - now falling in love with each other.