Knight Terrors: Catwoman (Knight Terrors: Catwoman #2)

Catwoman is stuck in a nightmare in which her sister, Maggie, parades around Gotham as its savior, Sister Zero. After rescuing Bruce from The Joker, Catwoman calls him Batman... to which he asks her how she knew that name, since he had only called himself that in his head. What year is it in this Gotham, why does The Joker have snakes for limbs, and can Sister Zero and Catwoman pray themselves out of this nightmare?