Three Kryptonian criminals led by General Zod team up with Lex Luthor to conquer Earth, forcing a depowered Superman to regain his strength and stop them.
Aiming to defeat the Man of Steel, wealthy executive Ross Webster hires bumbling but brilliant Gus Gorman to develop synthetic kryptonite, which yields some unexpected psychological effects. Between rekindling romance with his high school sweetheart and saving himself, Superman must contend with a powerful supercomputer.
A team of allied saboteurs are assigned an impossible mission: infiltrate an impregnable Nazi-held island and destroy the two enormous long-range field guns that prevent the rescue of 2,000 trapped British soldiers.
