Teen Titans Go! & DC Super Hero Girls: Mayhem in the Multiverse

At the Teen Titans' base, Beast Boy finds a strange crystal on the floor, pulsing with energy. The discovery hints at a larger crossover adventure and sets the plot in motion.

The superhero universe collides as Control Freak arrives at the Titans' base, bragging about a forced crossover. The Titans decide to watch the movie together, setting the meta-narrative in motion.

In the Super Hero Girls universe, Lex Luthor discovers an Amulet and uses it to rescue villains, forming the Legion of Doom. Their goal is to lock all heroes away in the Phantom Zone.

Cythonna, Kryptonian Goddess of Darkness, Plague, and Suffering, is locked in the Amulet by Rao, then banished into space years earlier. The Amulet's power remains dormant until the plot advances.

With the Amulet in play, the Legion of Doom causes chaos across Metropolis, challenging the SHG and their allies. The threat broadens as their master plan unfolds.

The SHG girls discover a Kryptonian rune in a park with Cythonna's name inscribed, hinting at the entity's true identity. Supergirl seeks help translating it, but Clark Kent is skeptical.

The girls travel to the Fortress of Solitude to gather information. They face off against Superman Robots and then the League; Wonder Woman halts the fight and ends up trusting Superman with the crystals, while Batgirl secretly steals crucial crystals and data.

Wonder Woman receives a secret call from Batman inviting her to meet at the Daily Planet. Together with Superman, they urge her to join the mission to stop Luthor and the Legion.

Jor-El's hologram message outlines Cythonna's plan to feed on the souls of the wicked, using a Kryptonian vessel to claim the universe. The heroes deduce that Luthor is being controlled by Cythonna and struggle to warn the League in time.

As the Amulet's crystal shatters, Cythonna grows stronger. The League is captured, with Superman imprisoned in a Kryptonite box and the others trapped in the Phantom Zone. Harley Quinn helps Wonder Woman escape and the team begins to fracture.

Bumblebee broadcasts an emergency call urging friends to reunite against the Legion. Harley Quinn decides to abandon the Legion and withdraws from the plan, shifting loyalties.

Wonder Woman reconciles with the SHG, and they return to Metropolis to confront the looming Legion. The UN is pressured to yield to the Legion's dominance.

Cythonna traps Supergirl and the others pursue a path through Zatanna's magic, ending up stranded in the Titans' dimension. The Titans help the SHG girls repair Bumblebee's computer to enable travel between universes.

In the Zone, the girls rescue their friends while Cythonna breaks free from the Amulet. Supergirl and her allies subdue the Legion, imprison Cythonna in a crystal, and banish her from their universe with Zatanna's aid.

Back in the Titans' universe, Cythonna possesses Control Freak to retrieve the crystal. The Titans and Raven thwart her, banishing Cythonna to the Super Friends' dimension, and deciding not to send the crystal back after all.