The story revolves around a Christian priest called Father Farera (Dev Anand) who is sent to jail through the connivance of a man called Chandulal (Ajit).
Chandulal rapes the forest woman and kills her, when Peter, who is Father Farera's friend goes there, Chandulal kills him too. Father Farera is a witness to both these crimes, and calls the police. However, Chandulal bribes the police as well as the Judge, to ensure that it is Father Farera who is arrested for the crimes and convicted for 14 years.
In jail, Father Farera makes good friends. He keeps tabs on Chandulal and his sons. Chandulal soon becomes the owner of diamond shop and one of his sons, Arjun is in Switzerland, also in the diamonds' business while his middle son is in Belgium. Both the sons are married but they tell that they are not married and rape them. However Chandulal's elder son Rahul (Manu Gargi ) is a good man. He is exactly opposite in character to his father and sons. Father Farera serves his prison term with the fire of revenge burning in his heart.
His sentence is reduced and he comes out of jail, only to become a 'Gangster'whose sole purpose is to destroy Chandulal who was responsible for his ordeal. He make a group with his jail friends. Father Farera becomes John. At Chandulal's elder son's marriage John comes as Mr. Blomo's secretary (A well known diamond merchant) and tells him that Mr. Blomo also want to do business with him. John detroys Chandulal and his sons' business and takes their money and runs. Chandulal complains to the police about John, but the police say that John is not Mr. Blomo's man. The police are now in search of John. Will the police catch John or Father Farera?