When his only sister and her husband die in an air crash, Rahul has to give up his studies, and take care of her three young children and his brother-in-laws' garment factory. To begin with the children drive him almost crazy, because the children play all sorts of tricks on him when he tries to be too strict a guardian. One day, the children sneak out of the house when Rahul, as a punishment some mischief of theirs, had locked them in. They go to fair and their they meet Vyjayanti. She is the daughter of a South Indian business tycoon, who has run away from home because her father insists that she marry a man, whom she considers to be a nincompoop, but whom her father thinks is a genius (just because the person happens is an avid fan of this art). The children and Vyjayanti hit it off at once; and since Vyjayanti has not told them who she is, the children bring her home thinking that they are sheltering a girl in distress. However, they are too scared to tell Rahul about her, so for a while they hide her. A hilarious sequence follows when the children are always one step ahead of their uncle in keeping her from being discovered. But finally Rahul does discover her. He believes sob story - and seeing that the children love her, he engages her as their governess. The inevitable happens. And Rahul and Vyjayanti fall in love. But the daughter of the businessman to whom Rahul's factory is in debt loves Rahul; and her father has bargained Rahul that either he marry his daughter, or suffer the wrath of a lethal businessman. Rahul is caught between saving the factory for the sake of the children - or sacrificing his love for Vyjayanti. How love triumphs in the most unexpected way is that "HUM HAIN RAHI PYAR KE" is finally all about.