Fancy Paths for plugins howto?

I’m wanting to write a plugin that will use multiple path levels, but I’m unsure how to get it to read beyond the first path level.

The idea is to create the_content filter on a page and from there build subsequent pages based on the path. Now I can get it work with _GET arguments, but I’d like to see it work in the fancy path scheme.

/comic/the_art_of_war/issue_2/page_4/

Thanks.