As Dr. Smith, the children, Debbie and the Robot look for ore, they happen across a maser teleportation machine left behind by the Taurons in "The Sky is Falling." Later, Penny and Debbie are caught in the beam when it activates, but no one is there to witness the event or do anything about it. Shortly afterwards, John discovers that Dr. Smith has the last of the supply the carbon tetrachloride which the family needs for food preservation. Smith, the Robot and Will go to look for Penny. They cannot find her but Smith orders the Robot to work the maser teleporter; Penny and Debbie reappear.
When Will realizes the alien machine can successfully transport matter anywhere in the universe, he runs to tell his father, but John more upset that Will was near the potentially dangerous machine without permission. John decides that the best course of action would be to destroy the machine. That night, Will decides he will use the alien machine to transport himself to Earth. Once there, he can contact Alpha Control and tell them where his family is so they can send out a rescue party. Will gets the Robot to transport him, and gives the Robot strict orders to transport him back at exactly noon the next day. Robot does as he is told, and Will is transported to Earth.
After arriving on earth Will meets a boy by the name of Davey. He introduces himself and explains how he got there, but Davey thinks Will is just making up stories. Will begs Davey to let him use a telephone, so Davey takes him back to his house. Will attempts a call to Alpha Control but the operator refuses to connect such a strange long distance call. Davey’s Aunt Clara thinks Will is a runaway with a over-active imagination and turns him over to the sheriff, who can only send him to the County Boys' Home. When Will continues to talk about outer space and Alpha Control, he is taken before the council of selectmen so that they can decide on a proper course of action. Will runs away again, and eventually ends up back with Davey and Aunt Clara.
Back in space, the Robinsons discover Will has gone missing and begin to look for him. Dr. Smith thinks the Robot will tell them that he was experimenting with the alien machine and tries to reprogram him. The Robot resists and refuses to allow it.
Davey and Aunt Clara both treat Will very kindly and even offer to adopt him, but Will is angry and depressed, worried that he will miss his appointed departure and be forced to stay on Earth apart from his family forever. Davey considers Will’s story for a while and eventually decides to believe him. Davey finally decides to help Will and takes him back to where he arrived, and even runs to buy him him a bottle of carbon tetrachloride to take back. Will thanks Davey and Aunt Clara for their help, and is transported away.
When Will arrives back with the Robinsons, he excitedly tells them the story of how he was on Earth, but they only smile and think he imagined the whole trip... until he presents the bottle of carbon tet. Moments later, the alien machine, already dilapidated and now weakened by further use, explodes.
- This is the first episode to give the name of the Robinson's crash site as Priplanus.
- There are numerous ways to spell Priplanus...the English subtitles on the DVD spell the planet, Priplanus.
- At the beginning of this episode, Penny gets trapped in the matter transfer beam. Penny, shocked and frightened hits her hand against the light beam, but it's like an invisible wall. However, when Penny returns, she retains no memory of her experience.
- Will repeatedly attempts to contact a Colonel Mason at Alpha Control, and according to the operator, a General - possibly the same officer seen in The Reluctant Stowaway.
- It's rather curious that while the rest of the United States has gone beyond "television" to "video screens", Hatfield Four Corners looks more like something from the 1940s, with magneto phones and an operator that connects all calls, including local calls.
- Carbon tetrachloride, used here as a component in the food preservation system on the Jupiter 2, was once used as a refrigerant and as a fire extinguishing agent. It is also toxic and causes liver damage and has not been sold over-the-counter since the 1940s. However, it seems to still be stocked in the Hatfield Four Corners hardware store.
- Given the large number of mutants and contaminating microorganisms on the planet, it's odd that the egg found by Penny and Dr. Smith would be edible.
- The maser matter transmission device is stated to be Tauron technology, a product of the race that attempted to colonize the planet in "The Sky Is Falling" several episodes back. However, the device does not resemble the device used for that purpose in that episode (it was a small dome on a lighted pad). Plus the Taurons took all their equipment with them at the end of that episode so this must be from another failed colonization attempt or just production constraints/sloppiness.
- The date of Will's trip to Earth seems to be in contention. The Jupiter 2 lifted off from Earth on October 16, 1997. Aunt Clara says they all remember the Robinsons and that it was last year when the launched from Earth. There is a Christmas tree visible in Aunt Clara's home and Davey wishes Will a Merry Christmas and a happy new year. This would seem to indicate that the month is December and the year was 1998. Yet, when the Jupiter 2 passes near Earth months after Will's trip to Earth in The Ghost Planet, the controller says the Jupiter 2 was lost a year ago, setting back earlier than Christmas 1998.
- The only solid evidence of Will Robinson's presence, other than a press photograph, was a hand-held communication device which was non-functional, but was quickly repaired by Alpha Control technicians and confirmed by manufacturing details and serial number as one of those with which the Jupiter 2 was equipped prior to launch.
- Along with "The Keeper: Part 1" and "The Keeper: Part 2", this is one of Bill Mumy's three favorite episodes.
- This is one of very few episodes to be shot on the general Fox lot rather than any special stage.
- Keith Taylor, who played one of the boys in the orphanage, would return as one of the "Space Hippies" in "The Promised Planet" (Frosh, Baby). He questions Will asking if Will knows what a stellar interferometer is. Will correctly responds "It's a device for measuring the diameter of stars" - a rare instance of LiS getting the science right. This real device was the brainchild of Albert Michelson, perhaps the first physicist who rigorously measured the speed of light.
- Helen Kleeb played the telephone operator and was concurrently filming Fortune Cookie in the same role. Kleeb was born January 6, 1907, and died December 28, 2003. Kleeb was also famous for playing Miss Mamie Baldwin on the Waltons. Kleeb also starred in many television roles during the 60's & 70's.
- Reta Shaw played the role of Aunt Clara in this episode. Shaw played parts in movies such as Polyanna and Mary Poppins. Shaw also starred in many 60's and 70's tv shows, such as Bewitched playing Hagatha (sometimes Aunt Bertha), and Martha Grant on The Ghost and Mrs. Muir. To list all her accomplishments in movie and tv would fill this page. Reta Shaw was born September 13, 1912, in South Paris, Maine, USA, and died January 8, 1982 (age 69) in Encino, California, USA
- Since when is celery considered to be food that is good for “sustaining hunger?”
- In this episode, Doctor Smith, Maureen and John are all amazed at the sight of an egg, claiming “We don’t have eggs on this planet!” However, in the second season, we see the family eating scrambled eggs for breakfast on more then one occasion. (But aren't they on a different planet in Season 2?)
- Both Will and John claim that alien transportation machine was owned by the Taurons. I assume that they are referring to the humanoid family of aliens from the episode “The Sky is Falling,” since those were the only aliens to arrive by transportation light beams rather then a ship. However, that family of aliens never spoke a single word to the Robinsons. So how do the Robinsons know the aliens were Taurons?
- When Will arrives on Earth, he tells Davey and Aunt Clara and the town Sheriff who he is, and then tells them he needs to contact Alpha Control to get them to send out a rescue party for his family. Will describes exactly where is family is, and even gives the star system and the name of the planet where they are located. (Apparently they’re on “Priplanus”) This is confusing, because in previous and following episodes, all the Robinsons including Will claim they have no idea where they are.
- When Will is on Earth, no one will believe his claim that he is Will Robinson. This is hard to believe. As the first family in space on a mission to help save humanity, wouldn’t the Robinsons have been globally famous? Wouldn’t there have been pictures of Will in newspapers and on TV? If there had been, surely at least a couple people would have recognized him!
- This is the first LIS Episode that Sheila Allen, who was Irwin Allen's wife, had a part in. Sheila played the part of the social worker. Sheila Allen would also play in "The Space Vikings," as well as "Princess of Space."
- The main town set appears to be one of the main western town streets used in popular tv shows of the time. The props and costumes appear to be a mish-mosh of whatever was available.