"One morning in Metropolis, on an imaginary day that may, or may not, ever happen . . ." Perry, Lois and Jimmy all get salary increases, but not Clark Kent. While his co-workers go out to celebrate their good fortune, Kent switches to his union suit and joins his cousin, who has summoned him to the Fortress of Solitude.
Just as Clark's poor job performance lost him a raise in pay, Superman's poor job performance has met with disapproval from Kandor's elders. His employment review finds him wanting in key areas and if he doesn't address these issues in the next six months, he'll be replaced by another Kryptonian.
The problems the Man of Tomorrow has failed to solve:
1. Restore Kandor to normal size
2. Find an antidote to green Kryptonite
3. Wipe out crime and evil
4. Guard Against . . . [not visible]
Kara Zor-El doubts that her cousin could complete these jobs in a century let alone half a year. However, Kal-El has a plan. He has constructed a Brain-Evolution Machine that will increase his mental power a hundred times. The machine is powered by all varieties of Kryptonite, so there is a danger, and the Maid of Might volunteers to take his place, as "the world can't afford to lose Superman!" But the Action Ace insist it's up to him to take the risk.
The Woman of Tomorrow flips the switch and, under maximum power, the World's Greatest Super-Hero can hardly stand the pain before the machine explodes and as the dust settles two Supermen emerge from the wreckage--Superman-Red and Superman-Blue.
They set out to enlarge the bottle city, but first they must create a world for the Kandorians to inhabit. At the fringe of the solar system, Red and Blue mould a planetoid that draws together all the Kryptonite in the universe. Once the matter has reformed into a giant planet it reverts back to its native state and is no longer harmful to Kryptonians. Enlarged on this new Krypton, the Kandorians are all Super-People under our yellow Sun and they set about rebuilding cities and krypto-forming landscapes such as they had on Krypton.
The Council votes whether to stay in this solar system or to return to the Rao system in another galaxy. They choose to get back to where they once belonged. Red and Blue have set the planet in orbit to return there.
Before the Superman twins can return to their to-do list, they get a call from Lori Lemaris and her friends in Atlantis. They also want to leave Earth for a world of their own.
The two Men of Tomorrow begin by finding a suitable planet with their Mind-Prober Ray, which locates the memorial planet of Krypton. Along with Kara and Krypto, their combined heat vision melts the polar icecaps and floods the entire memorial world.
They seem to have forgotten about Ronal's homeworld which is all water.
Red and Blue create a vortex in space that draws water from the ocean on Earth to the oceans on the new waterworld, dubbed Hydra. Not only do the mer-people make this interplanetary exodus, so does some of our sea life--which would seem to harm the Earth's underwater ecology, but oh well.
Note: In this story, Krypton was in another galaxy from ours. And yet the new planet is supposed to orbit from our galaxy to that galaxy, which doesn't make sense. If that could even happen, it would take billions of years. It seems more likely that Red and Blue opened up a warp in space that drew the planet into the Rao system.