Naina Catherine Kapur (Preity Zinta) is an angry young woman, for more than one reason. Her father committed suicide when she needed him the most, leaving Jennifer (Jaya Bachchan), his wife, to raise their children all alone. The only factors that redeem Naina's life are the toiling and tolerant Jennifer and Naina's bumbling MBA classmate Rohit (Saif Ali Khan)Aman Mathur (Shah Rukh Khan), a happy-go-lucky man, arrives in Naina's neighbourhood and soon changes everything with his contagious joviality and zest for life.Noticing the sadness of his new neighbors, Aman intervenes. His insistence on their activity, his revival of their financial success, and his enthusiastic optimism soon change their lives for the better. Although Naina is initially reluctant to enjoy the presence of Aman, she grows to like him and eventually she falls in love with him.Meanwhile, her friend Rohit has fallen in love with her, though he does not tell her because Naina tells him of her love for Aman before he has the opportunity. Rohit is persuaded into dating a bounty hunter, Camilla, by his family.Aman finds out that Naina loves him and tells her that he is already married. He then contacts Rohit and urges him to make a play for Naina even though he has been trapped into an engagement. Aman resolves this by having Rohit tell Camilla that he will inherit nothing, so she leaves the scene promptly.Aman has told everyone that he is married to Priya. This is revealed to be a lie, told by Aman to disguise the fact that he is dying of a weak heart. Aman, knowing that his own lifespan is limited, goes through life urging people to enjoy themselves and one another in the present moment, because "There may be no tomorrow".
