In search of Dr. Smith, the Robinsons land on a planet ruled by plants and become captured by Tybo, a giant carrot, who plans to turn the family into trees.
When the Robinsons come across an alien who controls time, Dr. Smith considers heading back to before he boarded the Jupiter 2 and changing the course of his life.
The Robinsons meet a group of spaced-out hippies who have been tasked to destroy the planet. The family have no choice but to get the Jupiter 2 back into space as soon as possible.
Professor Robinson only just escapes with his life when he is cornered by a hostile alien. But he was forced to kill it, meaning he is now the new prey of an interstellar hunter.
After accidentally passing through a time warp, the Robinsons crash land in New Mexico on Earth in 1947 and inadvertently kick-start the UFO craze of the era.
The Robinsons abandon their planet in a hurry to escape a collision with an approaching comet, and find a strange ship full of frozen, restrained passengers.
Penny is entrusted with a special belt by a dying alien friend, and she decides to protect it at any cost when a trio of nasty beings arrive to try and take it.
Will and Doctor Smith uncover a deep cave which, while they are investigating it, transports them back in time and space to Scotland during the 19th century.
The alien scientist Lemnoc captures Don, Judy, Penny, and Doctor Smith, replacing them with android duplicates while John and Maureen are away on a scientific mission.
The Robinson family meet a female alien and help her to build a portal device that will allow her people to travel to their world and begin colonization.
Verda comes to the Robinson family for help after she is marked for destruction by the Celestial Department Store, and a killer android is dispatched to eliminate her.
Will and the family are reunited with the swashbuckling Captain Tucker and his crew of space pirates, who are searching for the final clue in a hunt for legendary lost treasure.
Just hours before the launch of the Jupiter 2 on a journey home, Doctor Smith makes a startling discovery: a nearby cave inhabited by three part-biological, part-mechanical beings.
An encounter with a space wizard gives Doctor Smith with the opportunity to return to Earth in his spacecraft, but at the expense of the wizard's extravagant plans.
Will and Doctor Smith discover a seemingly abandoned ship that they begin to repair, only to find out that it belongs to a space pirate hunting down his mutinous crew.
Doctor Smith and Will discover an entire world inside of an alien machine which houses the Toymaker - a being who exists to create toys for the galaxy's children.
The family encounters a strange knight who has been wandering through space hunting the "Questling Beast". Penny accidentally finds and befriends the creature.
The strange alien being from another dimension who lured Doctor Smith into a trap returns, keen to ensnare the Doctor once again. Will undergoes a dramatic physical change.
The Robinson family find themselves caught in the middle of a war between a race of golden aliens and a race of green aliens. Penny befriends one of the green aliens.
The family robot is stolen by a mysterious group, who seem to want to replicate it over and over to build an army with which they can take over planet Earth.
Smith meets Zeno, a famed intergalactic gun fighter and Smith's spitting image. The two men agree to switch places and see what fun they can have living each other's lives.
Doctor Smith finds out that he has come into an inheritance, but it turns into more of a curse than a blessing when his long-lost cousin Jeremiah tracks him down to kill him.
Doctor Smith is lured into a deadly battle with a band of space gladiators. If he wins, the family will get to return to Earth. If he loses, he dies...
Doctor Smith claims to have built an android that the family befriend and try to help become human. Things take a turn when an alien arrives and asks for payment for the android.
The entire Robinson family is taken prisoner for crimes they did not commit, only for the evidence to show that Doctor Smith was the one responsible every time.
The Robinson family take shelter on a distant world, only to be attacked by a strange hermit and peculiar alien army who intend to take their ship for them.
Doctor Smith finds what looks like a habitable world for the family to rest on for a while, only to discover that it is overrun with unwelcoming cyborgs.