An unstoppable monster named Doomsday arrives on Earth, wreaking havoc and destruction across the nations. The world's mightiest heroes, The Justice League, led by Batman, Wonder Woman, The Flash, and Green Lantern, are quickly overpowered by the behemoth's sheer strength and resilience. Recognizing the threat Doomsday poses, Superman steps into the fray as humanity's last hope. The Man of Steel is forced into a brutal confrontation with the creature, with the safety of the entire planet hanging in the balance. As the battle ensues, Superman's commitment to protect and save life is put to the ultimate test.

The aftermath of the earth-shaking battle leaves the world grieving and in disbelief. Without its greatest defender, a sense of vulnerability and fear encompasses the globe. As Metropolis tries to recover from the substantial loss and damage, the absence of Superman creates a vacuum that new, disparate Supermen attempt to fill. These new individuals, each claiming the mantle of the fallen hero in their own way, emerge with differing agendas and abilities. The world, still reeling from its loss, must decide whether any of these new Supermen can truly replace the original, while a much greater threat begins to loom on the horizon.