Naive, milk-drinker, childlike Chhote Nawab, born on February 29th, lives a wealthy lifestyle in the Bombay-based Nawab family consisting of his widowed dad; sister, Mehnuma and her husband, Safdar. His father has borrowed money from Bhagwanti Lala through Safdar's prompting and is heavily in debt. When Bhagwanti gets a Court Order, the Nawab has a stroke and passes away, leaving Chhote at the hands of a merciless Safdar who beats, abuses, and drives him out. Unable to find work with the mind of a 5-year old, he is taken in by his dad's friend, Nawab Nazir Hussain from Calcutta, who had arranged his marriage with his daughter, Roshan, much to the chagrin of his wife. Upon arrival in Calcutta, Chhote is looked after by Nazir and Roshan, who educate him, and in about a year Chhote matures considerably, behaves according to his age, and romances Roshan. Then things change dramatically when Chhote starts making money through his race-horse, Roshni, substitutes milk with alcohol, starts getting independent, ill-tempered and bad mannered, and replaces Roshan with a cabaret dancer, Sophie!!