Kaho Naa... Pyaar Hai movie was Hrithik Roshan and Amisha Patel's debut and made Hrithik into an overnight superstar in Bollywood. Rohit (Hrithik Roshan) is an orphan and lives with his little brother and his foster family. He meets Sonia (Amisha Patel) and they are attracted towards each other.
Sonia invites him on a cruise with her and due to a freak accident they are separated from the main ship. They reach a small island and during their stay over there, their friendship blossoms into love. Sonia's father is initially disapproving but later agrees to their marriage, provided that Rohit gets more self-sufficient economically to support their family. On the day of Rohit's first stage show he witnesses an accident and the killers eliminate him in a motorcycle accident.
Sonia is grief-stricken and goes to New Zealand to get away from her past. But she is in for a big shock when she sees Raj (Hrithik Roshan) who looks exactly like Rohit. Raj gets to know Sonia and is attracted towards her but Sonia spurns his advances. Raj travels with her all the way back to Mumbai to persuade her, and on Mumbai airport he is shot at by the same man who had killed Rohit. Now Raj and Sonia are on the run away from the villains and should solve the mystery for themselves before the villains catch up with them.