The world's finest heroes found the Justice League in order to stop an alien invasion of Earth.

In the aftermath of Justice League: War, the world is at peace or so it seems. When Atlantis attacks the Metropolis for the death of their king. But the Queen has different plans and requires the Justice League to find her lost son. But while they search for him, Atlantian troops; led by Ocean Master, continue their assault. Who will win?

The gang goes on a trip to check on Velma's younger sister, Madelyn. She's been studying stage magic at the Whirlen Merlin Magic Academy, where apparently there have been sightings of a giant griffin. The gang decides to investigate.