The movie begins with the Justice League on a mission to stop Darkseid from destroying Earth. However, during their battle, Darkseid unleashes a strange energy wave that transports them to the world of Remnant. Upon arriving, they discover that they have been turned into teenagers and have lost most of their powers.
Meanwhile, on Remnant, Ruby, Weiss, Blake and Yang are dealing with their own problems. They have noticed strange changes happening on their planet, such as the sudden appearance of superpowered Grimm. The four huntresses are struggling to keep everyone safe and cannot figure out how to stop the chaos.
The two groups eventually cross paths and realize that they need to work together to solve the mystery of what happened to Remnant and how to stop it before it's too late. Along the way, they face challenges such as learning to adjust to their new teenage bodies, dealing with their own personal issues, and facing new enemies.
The team discovers that a rogue scientist is responsible for the changes on Remnant. She has been experimenting with Darkseid's energy and has unintentionally caused the alterations. Together, the team stops her and sets everything right again.
In the end, the Justice League is able to return to their own world thanks to the combined efforts of both groups. They part ways, but not before learning valuable lessons about teamwork and the importance of friendship.