Thanks to the orchestrations of Lex Luthor, terrorist John Corben becomes Metallo, a skin-covered cyborg with a Krytonite heart. Luthor then sets the supervillain on a quest to kill Superman.

On an island with an active volcano that is about to erupt, Metallo appears with temporary amnesia.

Clark Kent is thought to be dead after an automobile accident. Superman must nevertheless save an innocent man from execution and find the real culprit.