In 2058, Earth will soon be uninhabitable due to the irreversible effects of pollution and
ozone depletion. In an effort to save humanity, the United Global Space Force sends Professor John Robinson, his wife Maureen, daughters Judy and Penny, and young prodigy son Will on the spaceship
Jupiter II to complete construction of a hypergate over the planet Alpha Prime, which will allow the population of Earth to be instantly transported and populate the new planet. Penny rebels by breaking curfew, while Will's prize-winning science experiment involving time travel goes largely unnoticed by John. Global Sedition, a
mutant terrorist group, assassinates the
Jupiter II's pilot, who is replaced by hotshot fighter pilot Major Don West, to his chagrin. The family's physician Dr. Zachary Smith, a Sedition spy, sabotages the ship's on-board robot before launch, but is betrayed by his cohorts and left unconscious as the ship launches and the family enters
cryosleep. The robot activates and begins to destroy the navigation and guidance systems, en route to destroying the family. Smith awakens the Robinsons and Don, who subdue the robot, but the ship is falling uncontrollably into the Sun. Forced to use the experimental hyperdrive with an unplotted course, the ship is transported through hyperspace to a remote planet in an uncharted part of the universe. Passing through a strange distortion in space, the crew finds two abandoned ships in orbit: the Earth ship
Proteus, and another ship clearly not of human origin. They board the
Proteus, with Will controlling the now-modified robot. They find navigational data to reach Alpha Prime, and a camouflaging creature Penny calls "Blarp", along with evidence suggesting the ship is from the future. They are attacked by spider-like creatures; one scratches Smith, and the robot's body is irreparably damaged but Will saves its computerized intelligence. Don destroys the vessel to eradicate the spiders, causing the ship to crash-land on the nearby planet, where another distortion appears. Will theorizes they are distortions in time, as his experiment predicted, but John ignores his input. Exploring the time bubble, he and Don encounter a future version of Will and a robot he rebuilt with the saved intelligence. The older Will explains that surviving spiders killed Maureen, Penny, and Judy. Constructing a time machine, the future Will intends to return to Earth to prevent
Jupiter II from launching. Young Will and Smith investigate the time bubble on their own. Smith tricks Will into handing over his weapon, but is foiled by a future version of himself, transformed by his spider injury into a spider-like creature, who has been protecting Will since the rest of the family was killed. The present Will and Don return to the
Jupiter II with an injured Smith and the robot in tow, while the future Smith reveals his true plan: He killed the Robinsons, but kept Will alive to build the time machine, so Smith could return to Earth and populate it with a race of spiders. John, remembering that spiders eat their wounded, rips open Smith's egg sac with a trophy Will turned into a weapon. Smith's spider army devours him and he is thrown into the plasmic ring around the time portal, ripping him apart. The planet's increasing instability forces the
Jupiter II to take off, but they are unable to reach escape velocity and are destroyed by the planet's debris. Realizing his father never actually abandoned them, Will sets the time machine to send John back to his family, but there is only enough power for one person. Saying goodbye to his family, the future Will is killed by falling debris, and John reunites with his living family. Realizing they do not have enough power to escape the planet's gravitational pull, John suggests they drive the ship down through the planet, using the gravity well to slingshot them back into space. They are successful, but the planet turns into a black hole, and they activate the hyperdrive to escape. Using the
Proteus’ navigational data to set a potential course for Alpha Prime, the ship blasts off into hyperspace. ==Cast==