You would not want to come up with a storyline that is already being done by another filmmaker but that doesn't mean you don't have any right to do it. And going by the first come first serve basis some filmmakers take the first step and grab the pro...
The law of karma states 'What Goes Around Comes Around' and if you think it applies only to human destiny and fate then it may not be so. Even cinema industry is one place where things do come around after a while....