Gotham Academy: Endgame #1

Gotham City has been overrun by craziness, and the power is out at Gotham Academy! But don't worry. The kids are safely locked up, huddled around candles and flashlights and telling the Gotham City version of ghost stories: Joker stories! Meanwhile, a mysterious figure connected to the Academy's past is patrolling the grounds with a crossbow, but who is it?