The Fallen Realm is a ghastly dimension where Hippolyta hid the Oculus of the Argo after Hera tasked her with keeping it safe. The laws of physics are completely different so much that running rightside up means running upside down. Ruins of Greek temples and land masses float about in place. Lex Luthor and Circe stole Hippolyta's staff and went through a portal to the realm to steal the Oculus. Hippolyta performed a ceremony that ended with her pounding a gong and yelling "Anoikto!" (or "Open!"). A portal was generated and open long enough for Wonder Woman, Superman, and Batman to head through. A giant serpent followed them and nipped at Batman's heels until Wonder Woman smacked it on the cheek. Luthor placed the Oculus on his chest and gained the powers of Zeus, along with hair.
Circe ignored their warnings and decided to turn Wonder Woman, Superman, and Batman into a trees as a warning to anyone else who would try to cross her and Luthor. Superman blasted Circe away with his heat vision while Wonder Woman lassoed Luthor in time and forced him to admit he was going to double cross Circe after they conquered Olympus. Circe forced the Oculus off Luthor and zapped him repeatedly. She released Wonder Woman, Superman, and Batman from her spell. Superman took off after Luthor. Circe tried to sneak away but Wonder Woman already knew she'd try and lassoed her. They returned to Themyscira and Hippolyta regained her stolen staff.