Hamilton, Swan and Klein craft a Superman/Luthor story in issue 164 (Oct. 63) that heads in an unexpected direction.
Little time is wasted getting to the cover sequence. Luthor challenges Superman to a battle on a planet with a red sun, where Superman will have no powers, and they can fight as equals. Superman accepts, but finds the challenge much more difficult than expected. A storm separates the two men, and the next day they both finds themselves lost and wandering in the ruins of a formerly great civilization.
Luthor understands the machinery still lying around, unused, even though the inhabitants of the world have lost that knowledge. He is able to use their weapons against Superman, but cannot help their depleted water supply.
Still, by the time Superman finds Luthor, the people already think he is the greatest thing they’ve ever seen, and cheer him on in his battle with Superman. Luthor lets himself lose, and even Superman can tell this is happening, but cannot understand why. As they head back to Earth, Luthor points out a planet of ice, which could supply that of the planet they had left, and asks Superman to do so.
Superman is amazed, but does as Luthor asks. He shows Luthor a picture of the world, and the statue they have erected of him.
This planet, called Lexor when next seen, would become Luthor’s own personal heaven and haven.