The official account of Batman: Arkham City on Twitter has been posted an enigmatic image, where we can see a pair of boots and a hammer, accompanied by the phrase " don't worry, it's all part of my plan ." Clues suggest the lovely Harley Quinn, fueling rumors passed so that the upcoming DLC for Batman: Arkham City could be dedicated to her as well as Robin. It only remains to wait for new information and discover what will this future expansion.