A spaceship crash-lands in Gotham City Harbor, revealing a mysterious girl with powers similar to Superman's. Batman investigates and discovers that she is Kara Zor-El, Superman's cousin. While Superman becomes protective and tries to help Kara adjust to life on Earth, Batman remains suspicious of her origins and intentions. Wonder Woman suggests that Kara should undergo training on Themyscira to control her powers better. Reluctantly, Superman agrees, and Kara begins her training among the Amazons. However, Darkseid, the tyrannical ruler of Apokolips, takes an interest in Kara and plans to use her abilities for his own sinister purposes.

Batman and Superman soon realize that Darkseid has kidnapped Kara to brainwash her into becoming the new leader of his Female Furies. They enlist the help of Wonder Woman along with Barda, a reformed warrior from Apokolips who has defected to Earth. Together, they venture to the hellish world of Apokolips to rescue Kara and thwart Darkseid's plan. The mission tests their strengths and alliances as they face formidable enemies and moral dilemmas. Throughout their journey, the heroes confront not only physical challenges but also the psychological effects of Kara’s internal struggle with her identity and destiny. Their united determination aims to save Kara and prevent Darkseid from wielding her power for evil.