Master Sundardas, his wife and his daughter Bholi lead a happy life in their village. When Sundardas is transferred to teach in a high school in Bombay, his wife and daughter are overjoyed. Sundardas himself, however, is reluctant to leave his village behind.
Bombay is a whole new world to young Bholi. She sits at the window all day, fascinated by passing cars, trams and buses. Though she is a woman past her adolescence, she still speaks and thinks as innocently as a child. Their neighbours are Dayal, his cousin Maya, and their friend Prem. Dayal is an M.A. graduate, Maya is engaged in completing her B.T., and Prem is a civil servant. Soon, Dayal starts visiting Sundardas' home. As he grows more familiar with them, he takes a keen interest in Bholi. Meanwhile, Dayal's father Seth Chunilal has arranged his marriage with his friend Charandas's daughter. When Bholi's mother passes away, Dayal's maid Champa starts looking after her.
Dayal goes to his village for a while, and Maya lands a job in Delhi. The cunning Champa schemes to increase her own livelihood, and pushes Bholi and Prem together. Infatuated with each other, the two start meeting in secret.
Prem is called to Delhi urgently for some work, and he gets married to Bholi in a hurry, at a civil ceremony in court. The naive Bholi, on the other hand, has no idea what this entails. She leaves her marriage certificate, a mere piece of paper to her, lying around amongst her clothes. Missing Prem, she starts writing to him. Unfortunately, the letters are waylaid by Maya, who is also in love with Prem, and she disposes of them without informing him. Prem leaves for America.
On returning from the village, Dayal approaches Sundardas for Bholi's hand in marriage, and he happily accepts. Eavesdropping on their conversation, Bholi is devastated. She rushes to tell Dayal everything, including the fact that she is now pregnant. Dayal is hurt, and he turns her away. At Champa's suggestion, Bholi runs away from home. Unable to bear the loss of his daughter, Sundardas loses his grip on sanity. Dayal brings him home with him, and wires Maya to return, so she can help take care of the old man. Looking for Bholi, he reaches Champa's village. He is shocked to find Bholi in the midst of a marriage ceremony in which she is to be wedded to Champa's wily nephew. He rescues her, and adopts her as his sister on his return to the city. Tragically, Sundardas can no longer recognize his own daughter.
Prem returns from America, and Dayal prepares to go to Delhi to meet him. On the way, he is confronted by Champa's nephew. The nephew is wounded in the fight that ensues, and Dayal is arrested. Bholi's hopes are shattered when the newspaper informs her of Prem and Maya's impending marriage.
What happened next? See the rest on the silver screen.
(Translated from the official press booklet)