This issue is the conclusion of the BATMAN R.I.P. arc, and so is not the place to jump on. In fact the entire arc is tailored specifically for people like me, who have been reading Batman since the ’60’s. It is deliberately, self-indulgently arcane and obscure, as if to repel everybody who isn’t already deeply into all things Bat — a terrible marketing decision IMO.
Furthermore, analyzed purely as a story, the thing is elliptical, with many confusing cuts, flashbacks, unidentified characters, and allusions to things that may or may not have happened. Oh, and did I mention that Batman himself suffers a major mental breakdown and thus is the most unreliable of narrators? It might be best to wait for the inevitable trade paperback, so that you could read all the issues in order at one sitting; this would be your best prayer of figuring out what is going on.
I would have guessed this script to be unsaleable and unpublishable, except in a year where a blockbuster Batman movie came out. There is a balance between telling the reader all, and keeping all the cards close to your chest. This arc is a fine example of failing at the latter.