"This Planet is Mine!"
Still having doubts about his Kryptonian heritage, Superman has little time to worry about it, because a villainous duo are attacking Metropolis. To make things worse, both villains have powers that are radioactive in nature and they plan on turning Metropolis into a radioactive wasteland ruled by mutants.
Note: Ma and Pa Kent appear in one panel on a video-tape being played in the Fortress of Solitude.
This story runs from #307 to #309.