After the previous volume saw the end of the grand conflict between the Earth-based Fables and the evil empire which had dominated the story so far, The Dark Ages shows that problems may not be over as other ancient evils come to life, protective magic loses its cohesion, and some of the war wounded are still dying. The pieces are being put in place for future plot developments but there is of necessity noi resolution, so it's a slightly disappointing story on its own merits. The volume also includes a dubious extra, "Return to the Jungle Book", where Willingham (who has previously failed massively at Arabic culture) uncomfortably and unsuccessfully tackles India, or rather a parallel world that happens to look like India.
I saw somewhere (and now can't find) a complaint that Fables Vol 12; The Dark Ages should not have been allowed on the Hugo nominations list as such, that the rules specify "a story or story arc" and that this volume contains "The Dark Ages", "Return to the Jungle Book", and a couple of other stories, which should have individually been eligible. If that is what the rules say, and I didn't just dream it, then I feel their letter may be wrong and their spirit is being interpreted correctly - surely most people buy books, not story arcs? This is only the second year of the Hugo for Best Graphic Story and it is still finding its feet (Paul Cornell missed out on a nomination for Captain Britain last year through administrative error). (Edited to add: Thanks to coalescent and andrewducker for pointing out ajr's posts on this here and here.)