In Superman/Batman: Apocalypse, a spaceship lands in Gotham City containing a young girl with powers similar to Superman. Batman and Superman must decide what to do with her, as she claims to be Superman's cousin, Kara Zor-El.
Darkseid, a powerful villain, wants to control Kara's powers for his own gain. Superman and Batman must team up with Wonder Woman and the Amazons to protect Kara and stop Darkseid's plans.
The heroes must face off against Darkseid's forces on Apokolips, a dangerous planet ruled by the villain. With Kara's help, they must defeat Darkseid and save the universe from his tyranny.