Gotham City and all its residents are transported to a strange world through the machinations of Ra's al Ghul and the League of Assassins. Batman soon finds himself on the front lines of contact with a bizarre race of equines called "ponies" and must find a way to return his city to its own world. But with suspicious natives on his doorstep and a mob of psychopaths and killers rampaging through this world's cities, he is forced to defend the ponies from the most dangerous villains of two worlds.