October 31st in Gotham City—the scariest day of the year. It's the night when trick-or-treating can be terrifying and tragic. It's the night when people fear the darkness and beware the moonlight. It's the night they say he came home. For tonight two very different people receive invitations to a very special party. They will be charged with surviving the night in the most horrifying haunted house imaginable. The guests: the monstrous Midnight and the Dark Knight Detective. The host: The Joker. Welcome to Halloween in Gotham City.