Enter the Composite Batman/Superman! The Dark Knight and the Man of Steel are trapped inside the Brainiac protocol's deadly moon base, and this psychotic A.I. will not stop until it has merged with the beings it believes are its creators! And merging is exactly what our heroes are doing, as the deadly new fusion of the World's Finest duo emerges to wreak havoc in the name of Brainiac! Can Steel and Batwoman turn the tide and save their friends?