Raj Raibahadur (Raj Kapoor) lives a wealthy lifestyle with his father, a widowed businessman. One day Raj is sent to work in the countryside, Saraswati Dam. One day, his father visits to Raj his deceased mother wished for him to marry Chandra (Vijayalaxmi), the daughter of his rich family friend. Raj decides to write a letter to Chandra, which she completely ignores. But Chandra's younger sister Neelu (Nargis) acknowledges the letter and responds to it in Chandra's name. After few letters, Raj and Neelu fall in love, but Raj is still unaware that it is Neelu who writes to him. Just then Raj is diagnosed with tuberculosis, the same disease that killed his mother. Raj decides to pretend that he never loved Neelu and also insists that she should marry his physician friend, Dr. Kailash (Pran). He also flirts with Chandra to make Neelu believe that he does not love her. Chandra decides to end the suffering of her heartbroken sister. Upon learning the truth, Neelu accepts Raj as he is. Miraculously, Raj also becomes well and both lead a happy life.