Supergirl’s story gets the cover spot on Action 316 (Sept. 64), but Superman still has the lead spot. Once again, both stories are by Dorfman and Mooney.
Learning of the escaped con aboard the spaceship, Superman flies out to Zigi and Zagi’s homeworld. The crook gets knocked unconscious during the landing, but at least that alerts the boys that he is there. Thay make him invisible for a while, to taunt Superman, but eventually send him back to Earth.
The story then becomes about Zigi and Zagi trying to matchmake Superman with their sister, Zyra.
Superman gets out of this by finding Zyra’s lost fiancee, re-uniting the couple.
Although Zigi and Zagi do not return, I am certain I have read something, likely by Grant Morrison, playing with the concept of these two.
Supergirl, living with Zor-El and Alura on Earth, is depressed by the absence of her adoptive parents.
Zor-El uses a time viewer to explore how their lives on Earth will play out. It displays a future in which the Zygor, an alien monster, comes to Earth seeking vengeance on Zor-El, who had driven it away from Argo City.
The Zygor has the power to control the minds of Kryptonians, after eating a lot of red kryptonite (?), and forces Supergirl to choose between killing Superman or Zor-El.
Zor-El insists that they cannot possibly let this future come to pass, that he and Alura must return to Kandor, so the Zygor will never find them. This allows the Danvers to come back, and Linda is also re-united with Dick Malverne and Lena Thorul.
At the end, we discover that the Zygor was actually captured by Zor-El many years ago, and died in captivity. So the whole thing was a lie. Alura agrees to keep Zor-El’s lie, as they will “all be happier that way.”
Which is likely the best she could make of things, after being so rejected by her own daughter, who prefers the psychotic Earthling Edna Danvers.
I am also fairly certain that the Zygor returns in a later story.