Thakur Ranjeet Singh (Amrish Puri) has a crown with him which he claims to be of diamond & says that long ago his forefather had brought it from abroad.
Every year he gets build an arena, calls for fighters & challenges anyone to fight against his brother (Mahesh Anand) who is said to be a great fighter. Amrish Puri announces fight competition & challenges to win his brother but on a condition that the fight will be to death.
Mahesh Anand has been winning this fight for years.
One day a young fighter comes & Amrish Puri realizes to observe him that he is stronger than his brother. The fight starts & it was to continue till next day but the fighter is killed the same day by Amrish Puri's Goondas.
Years passes. One day, a young boy, Sanjay comes to Kiran Kumar who is the trainer of his fight & request Kiran to teach him to fight. As he is sent by Aruna Irani, Kiran takes him as his disciples. After training, first, he wins Amrish Puri's son.
Amrish Puri comes to know that Sanjay is the son of the same fighter whom he had killed years ago who is Kiran Kumar's disciple now.
Sanjay falls in love with Kiran's sister.
Sanjay wins another fight also. Now Amrish Puri ponders over it & tries all his tricks to kill him.
Did Sanjay take revenge of his father? For answer of this question, watch "BADMASH NO. 1".
(From the official press booklet)