Ray Ferrier is a divorced dockworker and less-than-perfect father. Soon after his ex-wife and her new husband drop off his teenage son and young daughter for a rare weekend visit, a strange and powerful lightning storm touches down.
After their father is called into work, two young boys, Walter and Danny, are left in the care of their teenage sister, Lisa, and told they must stay inside. Walter and Danny, who anticipate a boring day, are shocked when they begin playing Zathura, a space-themed board game, which they realize has mystical powers when their house is shot into space. With the help of an astronaut, the boys attempt to return home.
A team of space marines known as the Rapid Response Tactical Squad, led by Sarge, is sent to a science facility on Mars after somebody reports a security breach. There, they learn that the alert came after a test subject, a mass murderer purposefully injected with alien DNA, broke free and began killing people. Dr. Grimm, who is related to team member Reaper, informs them all that the chromosome can mutate humans into monsters -- and is highly infectious.
