Rip off?
that's funny reading that some think this is a Buffy rip off. If the writer had this idea since he was a kid, he probably got it here:
http://www.imdb.com/title/tt0734569/
And probably Joss Whedon too. But that's as far back as my IMDB-fu goes. Not that that is ripping off, inspiration has to come from somewhere.