Jor-El I takes his son and daughter-in-law to Antartic City to reveal that a legendary race known as the Krull weren't mythic, but real. There, his research tells him, the aliens crash-landed centuries ago.
Unfortunately, while in the Antarctic, a snowspeeder accident fells the elder Jor-El, placing him in a life-threatening coma. While waiting for any news from Dr. Gaf at the hospital, Jor-El rummages through his father's research at the antarctic base for any clues as to why his father might have insisted on coming to this region of Krypton. Instead of finding detailed notes on the Krull, though, Jor-El stumbles across something much more disturbing. His father has been tracking developments at Krypton's core. What he's found is that large deposits of uranium at the center of the world make Krypton effectively a nuclear bomb. A chain reaction has been building at Krypton's core. Within two years, the planet will hit critical mass and explode. He shares his findings with a small group of scientists, including his brother Nim-El—and is laughed down for his troubles. How, they wonder, could all other scientists on the planet have missed this data, if true?
Despite this initial ridicule, Jor-El takes his findings to the big leagues, giving a major presentation to the full Science Council. The reaction is no different—though his audience has a longer memory. One, perhaps remembering the failure of the Anti-Grav I in the previous issue, asks Jor-El if he expects the Council to pour "good money after bad in space travel".
Meanwhile, Jor the elder comes out of the coma only long enough to share his final words with Jor-El. He tells his son of the Krull space ship he found in an antarctic cave. This, he believes, will be the salvation of Krypton. Retrofitting its engines to current Kryptonian technology will save years of research—years he knows Krypton does not have. After imparting this wisdom, Jor-El the elder dies. His son weeps over his body in precisely the same way Kal-El will eventually weep over the body of Jonathan Kent.
After the funeral, Jor-El II attempts to go to Argo City to convince his other brother, Zor-El, of Krypton's impending doom. Along the way, they pass by Krypton's capital, Kandor, in time to see it ripped from the ground, then miniaturized, by Brainiac.
Aside from the terrible humanitarian cost of an entire city being stolen from Krypton, it is a tremendous blow to Jor-El, personally. Virtually all his political support came from Kandor. With Kandor gone, his struggle to convince the planetary populace of its impending doom will now be all the more difficult. As he's trying to cope with this loss, Kal-El, the mysterious stranger that's recently shown up on Krypton to help the Els, departs as well. Anguished, Jor-El is on the verge of giving up. Lara, ever the pragmatist, refuses to be bowed. "You can give up if you want to, Jor," she says, "but I plan to continue. I want our child to have at least one parent who refuses to quit!" And with that little splash of attitude, Lara subtly announces to Jor-El that she's pregnant.
Pulled back from the brink of depression, Jor-El finally manages to convince a committee of the Science Council to open up their purses for a little space research. He runs some test flights of his new craft. One such flight goes horribly awry, though, and the spaceship hurtles back towards the launch pad. Just as Lara and Jor are about to be killed by the incoming vessel, a passing alien deflects the test vessel to safety.
In gratitude, the Els declare that the alien will be the godfather of their child. When the child is born soon thereafter, the alien, Rol-Nac, names him "Kal-El", or "star child", during the christening ceremony.
The progress Jor is making in his personal and professional life is to be celebrated—but he knows its not going fast enough to save the whole planet in time. He must amass more political clout to give his experiments any real meaning. Thus, he makes a serious bid for full membership on the Science Council.
To do so, he decides to briefly return to his other interest: the redemption of criminals. Eager to find a lower-cost, more dramatic solution to Krypton's growing crime rate, he discovers a way to enter what he calls "the Phantom Zone". Demonstrating his Phantom Zone projector on a world wide broadcast, he is elected to the Science Council by an overwhelming majority.
His political position more secure, Jor can now begin working on the Council from the inside. Just as he starts to engage in the political debate over the issue of Krypton's evacuation, Dr. Mar-Ko of Antarctic City discovers the Krull spaceship that Jor-El I claimed was downed in the antarctic. Before Jor can celebrate this very good news, however, Jor's dreams of space travel are completely destroyed by a madman.
In a bid to use space-based weapons to take control of Krypton by fear, Jax-Ur, former head of the Space Center at Kryptonopolis, destroys Krypton's moon and all its colonists . . .