A space colony family struggles to survive when a spy/accidental stowaway throws their ship hopelessly off course.
Will and the robot try to rescue the kidnapped Prof. Robinson in a macabre world of orange grass, polka-dotted leaves, and animated rocks.
John falls into a cave containing a centuries-old mummy, whose spirit possesses John’s body.
The Robinsons encounter a militant boy who is determined to prove his superiority over the earthlings.
Will finds a rusted, more capable robot, but the Robinsons’ own robot warns him against rebuilding the device.
Will and Dr. Smith discover a device that transforms wishes into realities.
Penny discovers an extraordinary mirror which reflects a world that does not exist.
The Robinsons meet a space traveling Earth man, Alonzo P. Tucker, who was abducted by aliens in 1876.
The Robinsons encounter a family of crablike visitors who are far from friendly.
The castaways’ planet is visited by a being traveling the universe to collect creatures—two of every kind.
Will disobeys John’s orders to stay away from the matter-transfer unit and is transported back to Earth.
The Robinson women and Dr Smith become involved in a war between the leaders of two alien civilizations.
The Robinsons must turn Penny and Will over or face death.
The travelers are menaced by glowing creatures who are looking for a humanoid brain.
Penny discovers a deep cave inhabited by an invisible but seemingly friendly voice.
Smith sets off an explosion in a bog, arousing an invisible, indestructible, and irresistible, creature.
Will tries to brew dissension among shapeless aliens who plan to conquer Earth.
Dr. Smith and the women discover that their spaceship has been looted.
Penny shelters an interplanetary fugitive who gives her a small disc that is supposedly the key to the greatest treasure in the galaxy.
Dr Smith and Will befriend an old miner named Nerim. After a series of earthquakes indicates that the planet is breaking up, Dr Smith tries to convince them that it is merely the effects of mining, and no harm will come to the planet. John informs him that he is wrong and that the Robinson family will be departing within the day. It is a race against time to escape the crumbling planet.
Visitors from Andronica are looking for a king – a position Dr. Smith feels uniquely qualified to fill.
John is captured by a maniacal humanoid and made the quarry in a sadistic big-game hunt.
A time warp transports the travelers to a hostile planet – Earth as it was in 1947.
A blue mist causes the travelers to disappear one by one until only Will is left.