We get an opening scene that shows the destruction of Krypton and features cameos by Zod and Brainac. Jor-El sends baby Kal-El to Earth, landing in smallvile. We show young Kal-El being raised in Smallvile by Jonathan and Martha Kent, eventually he grows and starts to realize that he has powers. We get all the growing up stuff, with great power, etc. Clark uses his powers to save people in Smallvile, becoming a local legend. Eventually Jonathan Kent dies, teaching Clark a lesson that he can't save everyone, but he should just try and be the best person he can. Clark also discoverers the Fortress of Solatude and sets it up as his base, becoming the hero known as Superman.
Clark moves to Metropolis and works at the Daily Planet under Perry White with Lois Lane and Jimmy Olson. Lois is feisty and independent, but there's a clear attraction between her and Clark. Jimmy hero worships Clark. Clark has secretly been acting as the hero known as Superman. Superman for a a TV interview in which he reveals his alien heritage, but tells people not to worry, as here's only here to help.
Clark, Lois and Jimmy are set to cover the launch of a new military amror developed by billionaire CEO Lex Luthor. Luthor sees himself as the hero of Metropolis, and these new armor will allow the police to keep the peace. The suits are equipped with a special green rock that was found in a crash site in Smallvile. The rock makes Clark feel uneasy. Suddenly the event is attacked by criminals belonging to the group known as Intergang, a criminal organization led by gangster Bruno Mannheim. Clark sneaks away and suits up as Superman. He stops the armor from being stolen, but accidently cripples one of the criminals, John Corben.
After a comedy sence where Clark explains his absence to Lois. We get a montage of him saving people and investigating Intergang. He works with cops Maggie Sawyer and Dan Turpin to try and being Intergang down. He discovers they've been attacking rivals of Luthor, and that Luthor has been supplying them with advanced tech. Luthor hired them to steal his own suit.
Meanwhile, Luthor has his assistant Mercy retrieve Corben. Luthor reveals that he doesn't trust Superman, and doesn't think an alien can be trusted to protect the world. He offers Corben a chance for revenge. He has his engineers repair Corben, turning him into a cyborg known as Metallo. They equip him with the rock. Superman takes a sample of the rock he found to the Fortress, where he discovers it's called Kryptonite and comes from his own planet. It weakens his power.
Clark finds out that a cyborg is attacking Metropolis. He arrives to fight Metallo but is badly beaten when he uses the power of the Kryptonite. Clark escapes. Clark goes to the Fortress, and talks to the projection of Jor-El. Clark decides he can't give up.
Metallo kidnaps Lois and Jimmy, and Clark arrives to fight him. Clark is able to stand his ground, and eventually the people of Metropolis rise up to help Superman fight Metallo. Metallo is defeated and taken in the by the government, where Clark meets federal agent John Jones, who seems strangely familiar with him. The Kryptonite is stored in the Fortress.
Clark reveals his identity to a shocked Lois, and they start dating. Clark appears before Luthor in his office, and tells him that while he can't prove it, he knows he was behind everything, and he'll be watching him. After Superman leaves, an angry Luhtor swears revenge and tells Mercy to ready the warsuit.
The film ends with Clark flying off to save the day again.
