Young Alan Parrish is sent to the jungles of Jumanji as he plays a mysterous board game. Twenty-six years later he is set free when two children play the game. Together they must outwit the powerful game, before new problems occur.

Professor Szalinski's invention accidentally shrinks his children to miniature size. They are unwittingly swept up and tossed out in the trash. Trying to trek back to the house through the jungle of their backyard the kids find themselves in a world where insects and lawnmowers have become giant life-threatening menaces.