There is an excellent article by Joe Clifford Faust on his website The Word Foundry about the rather limited number of situations available as plot material for an author. Joe covers this often cloudy area of “stolen ideas” in a very interesting post. Here’s some excerpts:
“According to a gentleman named Georges Polti, there are only 37 Dramatic Situations in the whole entire world.”
“In other words, in the mind of a writer, one good idea can give birth to another. And often the offspring bears absolutely no resemblance whatsoever to the parent. You have to understand this aspect of writing in order to make use of it to your advantage. If you don’t, you’re either going to be a very unhappy writer or you’re not going to be a writer at all.”
“So to boil it all down. What makes us original is not the basic gist of the plot. There aren’t that many to go around.”
The Lost Children: A Charity Anthology