The film is about Anand Sehgal (Rajesh Khanna), a cancer patient who, despite knowing this fact, believes in living his life to the fullest. Contrasting Anand is Bhaskar Banarjee (Amitabh Bachchan), a sober doctor, upset with life and the dark reality of his nation. Bhaskar's tête-a-tête with Anand makes him notice the colours behind all the despair and complexity in one's life and teaches him a lesson. After spreading happiness everywhere around himself and changing the lives of many, Anand as destined, leaves them all, which inspires Bhaskar to write a book on his life.
The film is a narrative, as Bhaskar writes in his diary about his life before Anand, his first meeting, how his relation with him changes from a doctor-patient to a friend, and then to a friend for which he can do anything, and how a dying man leaves his thinking changed to such a great extent