In the wake of his previous heroic acts, Superman continues to live his dual life as the mild-mannered reporter Clark Kent and the revered superhero protector of Metropolis. Meanwhile, in a prologue sequence dating back to the ending of the first film, the nuclear explosion Superman thwarted inadvertently shatters the Phantom Zone, a prison dimension, freeing three Kryptonian criminals: General Zod, Ursa, and Non. The trio of super-powered villains, brandishing identical abilities to Superman due to Earth's yellow sun, begin a reign of terror across the world, culminating in their subjugation of the human race and food for their ambition of universal domination.

Parallel to this escalating threat, Superman grapples with his love for Lois Lane, who has become increasingly suspicious of Clark Kent's frequent disappearances and unusual coincidences linking him to Superman. As their romance deepens, Superman faces a personal dilemma, struggling with the responsibilities of his powers and his desire for a normal life with Lois. While considering the gravity of his role as Earth's guardian against the newfound danger posed by Zod and his cohorts, he must confront the ultimate sacrifice that may be required to maintain his secret identity and protect those he holds dear.