Luthor has imbibed a liquid form of Kryptonite, temporarily infusing his body with its radiation, and making him dangerous to Superman and taking on the identity of the Kryptonite Man. When Superman tries to make a lead suit to defend himself, Luthor makes an artificial satellite that turns all lead to glass. Superman then must get inventive to beat The Kryptonite Man.
- Although not mentioned in this story, Superman had already met a Kryptonite Man before Luthor. Superboy first encountered the Kryptonite Kid, who would later grow into another Kryptonite Man, in Superboy #83. Superman would have a series of battles against that Kryptonite Man.
- However, this issue was the first printed account of a Kryptonite Man. The story of his early meeting with the Kryptonite Kid was told later.
- Superman would later encounter a third incarnation of the Kryptonite Man, a member of a different humanoid race also from Krypton, in Superman #397.
- In the Modern Age continuity, Superman met a few different versions of The Kryptonite Man, including an alien entity from a Kryptonite meteor in Superman/Batman, and K. Russell Abernathy in "Up, Up and Away!"