The film is a story about the love between two Bombay teenagers of different classes ? Raj Nath (Rishi Kapoor), son of a rich businessman Mr. Nath (played by Pran), and Bobby Braganza (Dimple Kapadia), daughter of a poor Anglo-Indian Christian fisherman Jack Braganza (played by Prem Nath).
The couple first sees each other during Raja?s birthday party, and meet when Raja goes to see his old governess, Mrs. Braganza. There, he sees her granddaughter Bobby, and it is love at first sight for him. Raja and Bobby go to see a movie but find out it is closed. Then Raj gets an idea to go to a party. At the party Bobby sees Raja talking to another girl and thinks he is using her. As the story progresses, Raja realises that his relationship with the daughter of a poor fisherman is not taken kindly by his eccentric father. Upon Raj?s insistence, Mr. Nath visits Jack to initiate talks of Raj and Bobby?s wedding. But instead, Mr. Nath accuses Jack of using his daughter?s beauty and charm to trap Raja for his money. He even offers Jack cash to have Bobby stop seeing Raj. Jack feels highly humiliated by this accusation and reciprocates by insulting Mr. Nath. Their talk enters a deadlock and spells doom for Raja and Bobby?s tender love.
Mr. Nath engages Raj to a mentally challenged girl, Alka (Farida Jalal), in order to establish business ties with her rich father. But Raj runs away from home, to unite with Bobby. They both run away together. Mr. Nath advertises a reward for anyone who can help find his son. Prem Chopra (Prem Chopra) decides that he wants the money, and he and his goons kidnap Raj and Bobby. When they try to escape, Prem starts beating Raj. Mr. Nath and the police come to help, and they find Jack already there attempting to help Raj. Raj and Bobby run away from their fathers and jump over a waterfall. Both Mr. Nath and Jack jump into the water after them. Mr. Nath rescues Bobby, while Jack rescues Raj. They realize that they love their children very much, and don?t want to stand in the way of their happiness. They accept each other?s kids as their own and give their blessings to the union.