With global superpowers engaged in an increasingly hostile arms race, Superman leads a crusade to rid the world of nuclear weapons. But Lex Luthor, recently sprung from jail, is declaring war on the Man of Steel and his quest to save the planet. Using a strand of Superman's hair, Luthor synthesizes a powerful ally known as Nuclear Man and ignites an epic battle spanning Earth and space.

Hildy, the journalist former wife of newspaper editor Walter Burns, visits his office to inform him that she's engaged and will be getting remarried the next day. Walter can't let that happen and frames the fiancé, Bruce Baldwin, for one thing after another, to keep him temporarily held in prison, while trying to steer Hildy into returning to her old job as his employee.