Rakesh Roshan's Koi Mil Gaya is the story of Rohit Mehra (Hrithik Roshan) who shows the world that friendship is truly universal. Sanjay Mehra (Rakesh Roshan) is a scientist obsessed with establishing contact with extraterrestrial life. He invents many innovative gadgets till finally he succeeds in creating a computer that can transmit messages to space. His foresight becomes reality when as a response to his signals; a spaceship is sighted in the sky. But before Sanjay can enjoy his success, his wife Sonia (Rekha) and he meet with a horrific accident where Sonia survives but Sanjay loses his life.

Sanjay's son Rohit is born; a mentally challenged child who faces ridicules in every phase of his life. His lone companion is Nisha (Preity Zinta) whose compassion draws her towards Rohit. One day Rohit discovers his father's old computer and calls Nisha to help him use it. Both of them are completely fascinated by the images and instructions that appear on the screen and relentlessly experiment with the gadget not realising the impact this would have.

The whole town witnesses a blackout and a bizarre phenomenon. in an incandescent glowing sky. a colossal spaceship is sighted. However more strange findings were in store for Rohit's town - a pair of footprints not belonging to man or animal is found. What do Rohit and Nisha find out? Is danger lurking somewhere close? A nation holds its breath.

'Koi Mil Gaya' is the first sci-fi film made in Hindi, with the finest special effects ever been created in Indian Cinema. With 'Koi Mil Gaya', Rakesh Roshan has once again created history after the phenomenal success of 'Kaho Naa. Pyaar Hai', which catapulted Hrithik Roshan to dizzying heights.