Superman and Batman - longtime allies - are at odds when confronted with a crisis. Earth has been secretly overrun by two races from beyond the stars. One race uses everything in its path to assure its propagation and survival, the other is a culture of hunters, bound to a strict code that reduces every encounter with outsiders to a battle against becoming their prey.
The Man of Steel and The Dark Knight are Earths first line of defense. But they cannot agree how to deal with the Aliens and the Predators. For, as ruthless as these creatures are, Superman feels that all life is sacred and must be protected, while Batman cares about protecting humanity above all.
But their hand may be forced by an outside agency dedicated to the extermination of all interplanetary intruders, and all who are seen to protect and abet them. And that may include our heroes!