Penny will not give up the belt entrusted to her by an alien even if it means their deaths

Will and Dr. Smith find a cave that transports them to Earth, 19th-century Scotland.

The planet is invaded by an army of tiny robots who closely resemble the Robinsons' Robot and proclaim him as their long-predicted king. The Robot agrees to become their king, but when he is not the ruthless ruler they expected, they decide that he needs some "Dr. Smith" in him.

While John and Maureen are away observing volcanic activity, the alien scientist Lemnoc captures Don, Judy, Penny, and Dr. Smith and replaces them with android duplicates. Lemnoc then forces Will and the Robot to train the duplicates in survival skills, hoping that they will be an inspiration to his own people, who are losing the will to live.

While in the Valley of Shadows the Robot is affected by strange forces and grows to the size of a building. Will and Dr. Smith enter the Robot to try to reverse the process and save him.

A female alien meets the Robinsons and uses them to help erect an arch to bring her people to colonize the Robinsons' planet.

In the second of two sequels to Lost in Space: The Android Machine (1966), Verda's sheltered by the Robinsons after she's marked for destruction by the Celestial Department Store. To that end, the store dispatches a killer android: IDAK (Instant Destroyer And Killer).

Dr. Smith, Penny and Will are out playing a game and Penny finds a gold coin on the game board. They then find a trail of the gold coins and Dr. Smith falls into a cave containing a skeleton of an alien along with a old treasure chest. The Robinsons then have another encounter with the notorious space pirate Captain Tucker.

Shortly before lift-off, Dr. Smith discovers a cave inhabited by devices, which are the remnants of a once-mighty civilization; the Draconians. As the countdown draws near, Dr. Smith falls ever-more-so under the influence of the Draconians.

Smith is keen for the job of sorcerer's apprentice after learning that a space magician's rocket ship can reach Earth in a few hours.

Through some harmless playacting, Dr. Smith unintentionally conjures up the magical gauntlets and war hammer of the Norse god Thor. Taking him for a mighty warrior, Brynhilda spirits Smith off to Asgard for a showdown with Thor.

A space pirate looking for his crew that mutinied finds Will and Dr. Smith trying to repair his empty ship.

Doctor Smith and Will discover a old android machine from the Celestial Department store and end up getting sucked into the machine. There they meet a toymaker who refuses to believe that they are both human.

Sagramonte a knight errant, comes to the planet in search of Gundemar The Questing Beast. He then takes Dr. Smith and Will hostage.

Athena, the green girl from "Wild Adventure" who lured Doctor Smith out into space, returns and is still in love with him. Her suitor from the Green dimension follows her and turns Will green.

Beauty meets the beast, two aliens fighting a war land on the planet and the Robinsons are stuck in the middle of things. Handsome golden man Keema and the frog faced alien have the Robinson's choosing sides, will it be the right one?

Sesmar cons Doctor Smith into using a special camera to take pictures of the Robinsons. They're personalities are then stolen from them for use in a Frankenstein type android that Sesmar is in the process of creating.

The mysterious Saticon's make a offer to the Robinsons to buy the robot. The offer is turned down and then in the middle of the night the robot disappears. Later it is discovered that the Saticon's are more than they seem.

Doctor Smith while out with Will discovers a golden Lyre on a pedestal in a stone arch. He strums it and is sent to what appears to be Hell.

Will and Doctor Smith are out and about and a swift gun named Xeno who is on the run from the law and happens to be a exact double for Dr. Smith trades places with him allowing the real Dr. Smith to be arrested in his place.

Jeremiah Smith shows up to kill Doctor Smith for his inheritance.

Will, Penny and Dr. Smith get involved with a thief that is searching for a princess

Dr. Smith ends up in a boxing match with some space gladiators. If he wins he will return to Earth, and if he loses it won't matter because Earth won't be there.

Doctor Smith creates an android that they teach to be more human. A humanoid shows up looking for payment for the android.

The Robinsons are tried for space crimes and the evidence shows that Smith is really responsible for the mishaps.

A space circus comes to town and the owner wants Will to run away with it.

The Robinsons encounter a hermit who plans to attack the Jupiter 2 with his army.

Due to Smith's actions the crew has had to land their ship on an alien planet which is run by cyborgs. Meanwhile the crew try to break free from the captors who promise them power and luxury and they have to save their robot who was crippled by a ray gun.

Shortly after leaving their original crash-site planet, Smith spots a familiar star and, in an amazing show of stellar navigational skill, calculates the course to get back to Earth. He extracts a promise from Don and John that they'll return to Earth, or else he'll destroy his navigation data. They agree, but inform the family at dinnertime that they are headed for Alpha Centauri after all, mainly because the Earth is on the other side of the Sun (how do they know that? - do they know the date? And besides, from Alpha Centauri, Earth revolves clockwise, visible all the time). Smith changes course 180 degrees, then clumsily jettisons most of the fuel. They reach a refueling barge, one of several that Alpha Control put out in 1996, top up the tanks, and resume course for Alpha Centauri, not knowing that they've picked up a tailgater who follows them after Smith reverses course to Earth again. The alarm goes off in the night, and they expend a lot of fuel pulling away from the Earth's

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.