Spencer hides the pieces of the Jumanji video game, repairs the gaming system in his basement and gets sucked into the universe. Spencer's friends Bethany, Fridge, and Martha arrive to see Spencer missing along with the game being open and decide to re-enter Jumanji to save him. They witness the unexpected changes and move through the terrains of the most dangerous game in the world.

Agent H and Agent M are on a mission to protect the earth from the deadly aliens and must also tackle the biggest threat present within their own ranks.