Brothers Walter and Danny, constantly at war with one another and neglected by their preoccupied father, find their routine afternoon disrupted when Danny discovers a mysterious, metallic board game in the dusty basement. Entitled *Zathura*, the game features a clockwork-driven spaceship token and a treacherous path leading to a glowing golden planet. Ignoring Walter's initial disinterest, Danny initiates a turn, triggering a card that spews from the brass console: "
Meteor shower. Take evasive action." Within seconds, glowing space rocks puncture their living room roof, revealing that the suburban house has been physically ripped from its foundation and cast into the freezing, airless vacuum of deep space.Panicked and bewildered, the siblings realize the rules are absolute: they cannot stop playing until someone reaches Zathura and wins, or the game is permanently lost. Each subsequent turn escalates the peril. A rogue, automated Zorgon heat-seeking robot mistakes their home for a hostile vessel, forcing the boys to defend themselves. Shortly after, they rescue a stranded, rugged astronaut whose own game was ruined years ago when he rolled a catastrophic card and became trapped as a perpetual player.
The astronaut becomes a surrogate older brother and mentor, helping Walter channel his resentment into protectiveness and teaching Danny courage.As the cosmic journey intensifies, the gravitational pull toward the center of the board increases. Walter, driven by a deep-seated guilt over not being a better sibling, confronts his fears when he draws a card commanding him to sacrifice a crewmate. Meanwhile, a massive fleet of reptilian Zorgon warships surrounds the house, boarding the structure to pillage and destroy. The tension peaks when Danny finally reaches the center square, claiming victory. However, a treacherous Zorgon leader corners them, demanding the game. Utilizing quick thinking, Danny uses a wish granted by the game—obtained earlier—to wish that the astronaut’s brother had never been lost, revealing that the astronaut is actually an adult version of Walter who won the game in an alternate timeline.With the paradox resolved, the Zorgons, the ship, and the cosmic anomalies vanish in a brilliant flash of light. Walter and Danny suddenly find themselves back on the living room floor, exactly where they started, with the meteor damage undone. Transformed by their harrowing interstellar ordeal, the brothers share a newfound mutual respect, emerging as inseparable friends while their astonished father walks in, completely unaware of the universe-saving adventure that just transpired in their own home.