Trama

After the death of Superman, several new people present themselves as possible successors.

The Death of Superman (2018) and Reign of the Supermen (2019) now presented as an over two-hour unabridged and seamless animated feature. Witness the no-holds-barred battle between the Justice League and an unstoppable alien force known only as Doomsday, a battle that only Superman can finish and will forever change the face of Metropolis.—Anonymous

When Superman/Clark Kent is killed in The Death of Superman (2018), his parents and Lois Lane mourn. A lot of copycat Supermen pop up to fill the gap, all claiming to be Superman. Soon, they're fighting each other until a wormhole opens and a lot of monster villains attack Metropolis and the president. It takes all of the Supermen and the Justice League to fight them off. Unfortunately, the wormhole swallows up the Justice League before crashing. When one of the Supermen builds an army to take over the planet, it's up to Lois Lane, Lex Luther and the other Supermen to defend Earth.—Scott Filtenborg

Six months following the death of Superman at the hands of Doomsday, the crime rate in Metropolis has spread, while four new Supermen have emerged and become controversial to the world. There is a growing sense that humans should stop relying on the Justice League or the Titans and start saving themselves.

Lois Lane (Rebecca Romijn) and Clark Kent's (Jerry O'Connell) adoptive parents are still in mourning over his death. Superman's body has disappeared and Lois wonders if any of the new Supermen are really Clark reborn. Lois has been investigating the new Supermen by gathering information from different sources. Lois meets Diana Prince/Wonder Woman (Rosario Dawson) as well to gather her knowledge. Wonder Woman considers Lois a friend but doesn't know anything about the new supers. She says that the League is stretched thin since they lost Superman as the world depended too much on him.

Lex Luthor (Rainn Wilson) introduces a new Superman to the world at a press conference, which Lois discovers is actually a clone - Superboy (Cameron Monaghan) created by Dr. Dabney Donovan (Trevor Devall). Superboy lacks maturity and Lex has a tough time trying to control him in front of the media.

However, the conference is interrupted by the Eradicator (Charles Halford), Steel (Cress Williams) and Cyborg Superman (Patrick Fabian) (who claims he is the true Superman). Eradicator had come to arrest Lex due to his criminal record, but Superboy fights him. Eradicator gets an upper hand on Superboy and is about to eliminate him, when Steel intervenes and fights Eradicator. Eradicator defeats Steel and is about to arrest Lex when Cyborg Superman arrives and stops Eradicator. They all fight each other until both the Eradicator and Cyborg Superman leave the battle after their energy runs low. They all want to corner the legacy of superman.

Meanwhile, the Eradicator is transferring his DNA to the deceased corpse of Superman in the Fortress of Solitude. That night, Cyborg Superman visits Lois in an attempt to convince her he isn't a fake. He says Krytonian technology is encoded in his DNA and that allowed him to rebuild himself and revive even after his death. Cyborg Superman says that Kryptonians death is not the end. He says that he activated the technology before he was killed. He claims that half of his memories are lost along with half of his body, which is now made of replacement parts.

The 2 Supermen are busy fighting enemies, while Superboy is only interested in celebrity endorsements and the fame that comes with being Superman. Lex gets frustrated at Superboy, for his childish actions (he is an attention seeker and hence the people don't take him seriously). Lex says that he has invested far too much money into Superboy and needs him to be focused.

The Justice League, accompanied by Superboy, are hired as bodyguards for the president (this gig was arranged by Lex to change Superboy's image and to show him as more responsible), who is announcing their new Watchtower. Lex wants the President to endorse Superboy as the one true Superman. The presentation is suddenly attacked by Parademons, summoned via a boom tube portal. The League is mysteriously transported to another planet (when the boom tube portal collapses on them) and declared dead while Cyborg Superman rescues the president and is announced to the world as the true Superman.

Lex is livid at Cyborg Superman being recognized as the true Superman. Superboy says that he did everything that he is capable of doing. Angered, Lex reveals to Superboy he also has his DNA and kills Dr. Donovan after the he explains to Lex that Superboy is the best clone they could create.

Cyborg Superman is secretly being controlled by Darkseid. Lois follows Cyborg Superman to a graveyard and finds him weeping at the grave of Terri Henshaw. Lois finds that Steel is in fact John Henry Irons, a friend of the real superman, who once saved his life. John says that he owes it to Superman to fill his void, now that he is gone. With the help of Steel, Lois discovers Cyborg Superman is the deceased astronaut Hank Henshaw who blames Superman for not saving him and his wife and has decided to destroy his legacy by impersonating him. Henshaw reveals to the world his new "Cyber Corps" militia, which are created by Mother Boxes infused with humans.

Steel tracks the Eradicator to the Fortress, where he learns that Superman is currently going through a revitalization cycle, and the two engage in a fight. The fight is broadcast to Lois' phone. Lois realizes that the Eradicator is a hologram from Superman's ship's matrix, created to protect Superman. Eventually, the fight is stopped when a powerless Superman is reborn, also donning a black suit. Through Henshaw's technology, Lex and Lois discover that Henshaw himself is being controlled by Darkseid (Tony Todd) from Apokolips, who created Doomsday and orchestrated its attack on Earth.

Superman, Superboy and Steel head towards Metropolis. Lex sends Lois to the Watchtower as he uses a Mother Box to rescue the League from the abandoned planet. Darkseid continues to torment Henshaw for his failure to keep Superman dead and attempts to open a portal for his arrival, using the Mother Box infused with Henshaw. However, Henshaw rips out the Mother Box inside him, also deactivating Darkseid's control over the Cyber Corps.

Just before Henshaw attempts to kills Lois, Superman arrives. Henshaw blames Superman for his wife Terri's death. Henshaw has the upper hand on superman and launches the watchtower into space to stop the justice league from helping Superman. But in space, sunlight hits the watchtower, and Superman eventually regains his powers from the sun and kills Henshaw by stabbing his forehead with blue kryptonite, also deactivating the Cyber Corps.

In the aftermath, Martian Manhunter (Nyambi Nyambi) disguises himself as Superman to announce Clark Kent's safe return with the cover up of him being missing during the Doomsday attack. Superboy was sent to live with the Kents and was named "Conner". In a post-credit scene, the League gather at the Watchtower to confront Darkseid themselves, with Lex inviting himself in.