This is the story of two brothers named Danny and Walter who barely get along even while driving their parents to distraction as their older sister tries to ignore them. While they played this old mechanical board game known as Zathura. However, after when the boys did their very first move, they find out that the game has flung them, not including their sister and their entire house are eventually drawn into an epic adventure when their house is magically hurtled through space. But in order to get back home they must continue to play the game. During the course of the story, the boys must overcome their personal ill-feeling held toward one another in order to survive. They are aided in this by a stranded derelict astronaut who appears as a result of the game. This astronaut is eventually revealed to be an older version of Walter, who had been trapped as a character in the game's world as a result of causing the disappearance of Danny, without whom he was no longer a player. Unless they finish the game and reach the planet Zathura, they could be trapped in outer space forever!