Action Comics #851

Trapped by Zod and Ursa in the Phantom Zone, Clark searches for a way to return to the pysical universe. Guided by Mon-El, the only innocent ever comitted to the Zone, he finds the place where Zod and Ursa were able to create ships that could penetrate the Phantom Zone, leading back to reality. It was here that they sent young Lor-Zod, now known as Christopher Kent, to Earth. And here, Superman has a chance to free the world from the rogue Kryptonians.