Rajesh's father, a rich business man winds up his business in Africa and starts off for India with diamonds worth Rupees twenty fiver crores. The diamonds were hidden in a leather belt with him when he died at Beirut airport before dying, he gave the belt to one Mr. Kishorilal and requested him to take his life's savings to his son Rajesh. But Rajesh does not get the diamonds. The diamond belt mysteriously finds its way into a bicycle tool-box belonging to Sanjay who is not even aware of it.
In his search for the diamonds Rajesh comes across Kaajal, Kishorila'l only daughter. Kaajal in childhood was betrothed to Sanjay and was separated from him. The two young men Rajesh and Sanjay create such a tremendous emotional dilemma in Kaajal's life that she is unable to decide which one will be right choice.
But a more explosive situation created by Saudagar Singh, an international criminal, turns Rajesh, Sanjay and Kaajal into pawns. Saudagar Singh has pursued the diamonds from Africa to India.
Who gets the diamonds eventually - Saudagar or Rajesh ? Who saves Kaajal's life and wins her love - Rajesh or Sanjay ? - is the fabulous and colourful story of romance and intrigue of 'Hum Kisise Kum Naheen".