The planet Krypton faces imminent destruction due to its unstable core; the result of depleting Krypton’s natural resources. The ruling council is deposed by the planet’s military commander, General Zod, and his followers during a coup d’état. Knowing that artificial population control and isolationism have ruined their civilization, scientist Jor-El and his wife Lara launch their newborn son, Kal-El, the first naturally born Kryptonian child in centuries, on a spacecraft to Earth after infusing his cells with a genetic codex of the entire Kryptonian race. After Zod kills Jor-El, he and his followers are captured and exiled to the Phantom Zone. However, they are indirectly freed after Krypton explodes.
Kal-El’s ship lands in Smallville, a small town in Kansas. He is raised as the adopted son of Jonathan and Martha Kent, who name him Clark. Clark’s Kryptonian physiology affords him superhuman abilities on Earth, much to his confusion. Despite his isolation from the community, he eventually uses his powers to help others. After revealing to a teenage Clark that he is an extraterrestrial, Jonathan reveals his concern about social rejection and forewarns him not to use his powers in public. Several years later, Jonathan dies in a tornado while refusing to let Clark use his powers to save him. After Jonathan’s death, an adult Clark spends several years living a nomadic lifestyle, working different jobs under assumed identities, anonymously performing good deeds, and struggling to cope with the loss of his adoptive father.
Clark eventually infiltrates a U.S. military investigation of a Kryptonian scout spaceship in the Canadian Arctic. When Clark enters the alien ship, he uses a Kryptonian “control-key” from the ship that brought him to Earth, which allows him to communicate with the preserved consciousness of Jor-El in the form of a hologram. Jor-El reveals Clark’s origins, the extinction of his race, and tells Clark that he was sent to Earth to bring hope to mankind for a better future. Lois Lane, a journalist from the Daily Planet newspaper who was sent to write a story on the discovery, sneaks inside the ship while following Clark and is rescued by him when she is injured by its security system. Lois’ editor, Perry White, rejects her story of a “superhuman” rescuer, so she traces Clark back to Kansas with the intention of writing an exposé. After hearing his story, however, she decides not to reveal his secret.
Meanwhile, Zod and his crew seek out other worlds that the Kryptonian race colonized long ago, only to discover that none of the outposts survived after Krypton abandoned them. Zod and the others eventually pick up a Kryptonian distress signal sent from the ship Clark discovered on Earth. Zod arrives and demands that the humans surrender Kal-El, whom he believes has the codex, or else Earth will be destroyed. Clark accepts, and the military hand him and Lois over to Zod’s second-in-command, Faora, at Zod’s request. Zod reveals that he intends to use a terraforming “world engine” to transform Earth into a new Krypton and use the codex to repopulate the planet with genetically-engineered Kryptonians, killing Earth’s indigenous life in the process. Clark and Lois escape Zod’s ship with Jor-El’s help, Clark defeats Faora and another Kryptonian, and convinces the military that he is an ally. Zod deploys the world engine and initiates the process in Metropolis and over the southern Indian Ocean, increasing the Earth’s mass and atmosphere.
Clark, now called “Superman”, destroys the world engine, while the military uses the spacecraft that brought him to Earth in an aerial strike on Zod’s ship over Metropolis, sending Zod’s forces back into the Phantom Zone. Zod survives and engages Superman in a destructive battle across Metropolis using his newly developed powers. When Zod attempts to murder cornered civilians as revenge for his defeat, Superman is forced to kill him. Some time later, Superman warns the government that, if they want his help, it will be on his terms. To create an alias that gives him access to dangerous situations without arousing suspicion, Clark obtains work as a reporter at the Daily Planet.