Yes, but the point is that the "plotline stealers" are retelling the story as their own work and profiting off it. None of which we are doing (I hope).. Obviously to summarize a story you need to present the plot thoroughly (you can't just say "the book Moby Dick was about a whale"). This is not at all the same as copying the entire script, with annotations added in. Cliffs Notes has never been sued for copyright infringement (AFAIK) and they give a far more in-depth view than we do.