Zooni Ali Beg (Kajol) is a blind Kashmiri woman who travels for the first time with her friends, Mehbooba (Sanaya Irani), Rubina (Gautami Kapoor) and Fatimah (Shruti Seth) to New Delhi to perform in a ceremony for Republic Day. On her journey, she meets Rehan Khan (Aamir Khan), a Casanova tour guide who flirts with her. Although her friends warn Zooni about him, she falls in love. On her last night in Delhi, Rehan and Zooni spend the night together and end up in bed. As Zooni is leaving the next day, Rehan comes and takes her away with him. Her parents arrive in Delhi to marry them. Zooni has a procedure done that helps her see again, but when she comes out of surgery, she finds out that Rehan was killed in a bomb blast in the city.
Malini Tyagi (Tabu) is a special intelligence agent brought in to assess the threat of the bomb blast, and the group responsible, an independent organization fighting for an independent Kashmir known as IKF. It is revealed that Rehan is the man who placed the bomb blast in motion, then faked his death so Zooni wouldn't come looking for him. He admits that he loves Zooni, but also concedes that he can never see her again because of his dangerous life.
Seven years later, Rehan is on another mission for the IKF. IKF has acquired a nuclear weapon but needs to get hold of the trigger, which is in the army's possession. Rehan steals it, but Tyagi has figured out his plan and sends forces to stop him. In the ensuing shootout, Rehan is injured. He makes his way to a remote house for help. It turns out to be Zooni's house. Zooni had become pregnant after Rehan's supposed death and has given birth to and raised her and Rehan's son. Zooni and her father save Rehan, though neither knows his real identity. Though initially distant from them, Rehan develops an affection for his son and the family.
Rehan eventually reveals his true identity to them. Initially hurt, Zooni refuses to let Rehan leave her again, and the two of them are married by her father. Tyagi has a report published about Rehan, warning the public that he is a terrorist. Zooni's father sees this report and confronts Rehan. Rehan accidentally throws Zooni's father off a ledge, killing him. He radios the IKF from an army officer's house but kills the officer when he discovers Rehan. ReadMore>