The first story centers upon Superman making a journey to Mars to help protect Earth's first colony there from an invasion of The Metaleks - the all-consuming mechanical creatures we first saw several issues ago. It turns out that they are the least of it and that the Metaleks are on the run from an even more insidious threat known as The Multitude. Since they appear on the cover, it spoils nothing to say that The Multitude have the appearance of angels with fangs and claws.
Grant Morrison's story seems well-paced enough but at the same time seems awfully derivative of his previous work. Morrison famously explored the base idea of Superman fighting angels during his now-legendary JLA run and one can't help but think of that story here. And even with Morrison's take on Superman being more of a thinker than a puncher, I still can't help but think this story would be more appropriate to Doctor Who than Superman. Rags Morales injects his usual energy into the proceedings with his excellent artwork but that doesn't change the fact that we've seen this story done before and done better.