Superman agrees to sacrifice his powers to start a relationship with Lois Lane, unaware that three Kryptonian criminals he inadvertently released are conquering Earth.
Entrepreneur Ross Webster teams up with a computer genius in order to realise his own evil intentions. When Superman obstructs his plans, he decides to destroy him.
With the world on the brink of a nuclear war, Superman takes it upon himself to destroy all nuclear weapons. However, Lex Luthor creates Nuclear Man, a force strong enough to take down Superman.
Superman returns to Earth after spending five years in space examining his homeworld Krypton. But he finds things have changed while he was gone, and he must once again prove himself important to the world.