Where can you get a good short story summary?

If you mean a site that lists the plots to short stories that are already written, pull up your search engine and type in something like "classic short stories" or "read short stories online" -- I've put in a link below.

If you mean a site that lists various plots you could use to write your own, pull up the search engine and type in "20 Basic Plots" -- I've put in a link below.

I've also put in a link to a question explaining how authors get ideas for their stories.