Insaniyat Ke Dushman is an action drama. The movie revolves around Kailashnath (Shatrughan Sinha), a renowned lawyer. A criminal businessman named Jagmohan Mishra (Kader Khan) comes to Kailashnath to fight a case for his son, who is charged for the murder. Honest Kailashnath, who knows that Jagmohan’s son is the culprit, refuses to accept this case. Jagmohan’s son is then tried in the court and hanged. Later, Jagmohan kills Kailashnath’s wife and son in front of him. Kailashnath tries to seek the help of police, but his efforts go in vain. It is then he decides to take the law in his hands and avenge his wife and son’s death. Will Kailashnath succeed in his mission?