Superman fights Wonder Woman, who is trying to stop him from using the “vanishing device” on himself.
It’s no big shocker that the device is the Phantom Zone projector, even though Azzarello hasn’t told us that yet.  It was pretty easy to recognize it as such.  Again, the “big reveals” in this story are neat and all, but the real meat is in the dialog and the big ideas.  Here, Wonder woman threatens to kill Superman before Superman can vanish himself: Humanity needs its God on Earth, and is willing to kill God to keep him.  You could probably teach several college philosophy courses on this idea alone.
And, of course, Jim Lee’s great pencil work.  He did this right after Batman: Hush, when he was at the peak of his powers.