When what appears to be a simple drinking bowl ends up in Bruce Wayne's hands, a horde of dark villains descend on Wayne Manor, intent on possessing it. Ra's al Ghul, the Penguin and Catwoman, as well as dozens of brutal mercenaries, all will stop at nothing to claim this mysterious chalice. As the battles build to a savage crescendo, many questions demand to be answered: Could this really be the Holy Grail of legend? Can even its apparently miraculous abilities keep Batman alive long enough to find out? And if it is the real Grail, what does one do with it?