The Automated Planet (as the Robot refers to it), which the Robinsons left in the previous episode, has launched a hyper-atomic missile at the Jupiter 2. It is a homing missile and seemingly cannot be avoided, but John comes up with a plan to evade the missile and it crash into a nearby planet instead.
The ship is damaged by the manoeuvre and must land on the planet as well. There are many weeks of repairs ahead, but no one can go outside because it is uncertain if the atmosphere is suitable for humans or not. John does not even want to send out the Robot as the fog at their landing site might prove corrosive. Smith does not care and sends the Robot out anyway. Robot is only outside a few moments before something happens to him and he breaks communication with the ship.
John is furious and forces Smith out to find the Robot. Smith wanders around outside for a short while, discovers fresh clean air (the Jupiter 2 is in some kind of a bubble of harmful air) before he sees a giant bird and faints. John and Don look around themselves but cannot find either Smith or the Robot. John sends everyone to bed, but Will stays up in case Smith comes back.
Will then sneaks outside to have a look around on his own. He is confronted by the same giant bird and an orange-haired man called Tiabo, who is not at all happy to see him. Tiabo, stating he is part of a military force, is convinced Will is part of an invasion fleet and locks him up in a cave where Smith and the Robot are waiting. Tiabo warns that if anyone tries to leave the cave, the giant bird will eat them. He then scurries off to contact his superiors.
Left in the cave, Will and the Robot worry and Smith drinks a strange liquid he has found. They overhear Tiabo’s transmissions, but Will thinks the messages are odd somehow, and notices a peculiar similarity in appearance between Tiabo and his superior. Tiabo mentions a secret weapon that he plans to use on the Jupiter 2, and Will decides they must escape to warn the rest of the family.
On the way back, it is discovered that the beverage Smith has been drinking is a liquid explosive and that he is now a walking bomb. Once back with the others, Smith must stay far away from everyone else in case he blows up. Will takes pity on Dr. Smith and agrees to go back to Tiabo to beg for an antidote.
Will finds Tiabo busy recording messages in the role of a superior officer, and calls Tiabo on the deception. He manages to convince him that they need not be enemies, and that they will leave when they can. Tiabo gives Will some pills that will neutralize the explosive and talks about moving away to the other side of the planet. Meanwhile, the Robot decides to use a detonator to blow up Dr. Smith. Fortunately, Will arrives in time to stop him and administers the antidote.
- The giant bird costume in this episode had been used previously in the Outer Limits' episode "The Duplicate Man" where it was a creature called a Megazoid. Janos Prohaska was also employed in that series as the creature.
- The bird costume was also used in several episodes of “Bewitched,” in one it was the extinct Do-Do Bird.
- The episode is essentially a character piece for Wally Cox as there is actually very little plot. The story with Tiabo actually doesn't get started until the third act.
- After landing on the new planet, John refuses to let Robot go outside to check the environment. Strange, considering the Robot is an Environmental Control Robot.
- When wandering around outside the ship, Will steps into a puddle of sticky substance. He notes that it is like glue, and claims, “If anything stepped in it, it couldn’t get out.” He then, however, gets out without the slightest effort.
- When Robot 'tests the detonator' to see if Smith is still explosive or not, he does so with Will standing shoulder to shoulder with the doctor. Had Smith indeed blown up, Will would have been killed as well!
- When the Jupiter II is being pursued by the Ghost Planet’s rockets, John orders Don to head to a planet in sector 360, which they crash land on, the same planet they will remain until the beginning of Season 3. Is this planet called Gamma 6, in reference to a later 2nd season episode, named "The Deadly Games Of Gamma 6?"
- The original working title for this episode was…wait for it….”The New Planet” - brilliant!
- The astrogator control stick has once again returned to the left, facing the camera. Maybe the astrogator has a built-in lazy susan mechanism?
- In the cliff-hanger refresh, we see the Robinsons looking out the round rear view-port of the Jupiter II farewelling the Ghost Planet. Where did this window come from? In previous episodes there was a door here, but it now magically appears in an alcove next to the crawl ladder.
- The rear view-port proves handy as it shows the missile hurtling toward the Jupiter II, almost to within touching distance of the ship’s hull. In the next exterior shot, the spaceship has ample time to employ its rock n roll manoeuvre, and easily evade the deadly weapon.
- In the same exterior footage of the spaceship evading the missile, the newly installed view-port at the rear cannot be observed.
- As the Jupiter II approaches for crash landing through the planet’s atmosphere, you can see the guide wires attached to the miniature craft glistening in the sun as it hurtles across the mountains.
- When Dr Smith goes looking for the Robot, he is carrying the laser pistol and holster in his arms. In the scenes just before the fog clears, he now has the gun holster slung around his waist.
- John is concerned about the atmosphere or the fog being poisonous and yet when they send Smith out of the ship they don't use the airlock; they open both doors, allowing the planet's air and fog into the ship. They also don't use spacesuits despite knowing nothing about the environment outside the ship.
- Despite knowing his father's concerns about the planet's atmosphere, and despite the disappearance of both the Robot and Dr. Smith, Will goes outside the spaceship wearing no oxygen mask.
- When we first see the scary chicken-picken monster lumbering its way to Will, its neck comb is tucked inside its collar. In the subsequent scene, the neck comb is now flapping outside the collar.
- And the humanoid alien on the planet (Tiabo) happens to speak perfect English.
- Tiabo tells Will that Dr. Smith should take 4 or 5 of the pills to neutralize the explosive liquid he drank. However, Dr. Smith is only shown eating 2 of the pills, yet he does not explode when the Robot tries to detonate him.
- The scene following the discovery that the liquid Dr. Smith drank was explosive is set some time the next day. By this time everyone is outside with no oxygen masks and the strange fog around the Jupiter 2 has dissipated. Yet no explanation is ever given as to the nature or cause of the mysterious fog.
- One wonders if the title of this episode is in any way a tribute to the famous pioneering 1950s science fiction movie "Forbidden Planet."
Dr Smith: [to himself] “Alone, always alone….and I’m frightened”
Maureen: [observing the damage after the crash landing] “A little scrubbing will get this smoke off”
Don: [to John] “This may be a new planet, but we’ve still got the same old Smith”
Robot: [after Smith orders it outside to check the planet’s atmosphere] “It’s awfully dark out there”
Robot: “You are filled with an extremely dangerous beverage. I suggest that Dr Smith be kept at a safe distance from the others”. Will: “Why?” Robot: “Because it is possible he may blow up at any moment”
Dr Smith: [to himself] “Poor Dr Smith is in trouble. Well, let him explode.”
- Guy Williams as Prof. John Robinson
- June Lockhart as Maureen Robinson
- Mark Goddard as Maj. Don West
- Marta Kristen as Judy Robinson
- Billy Mumy as Will Robinson
- Angela Cartwright as Penny Robinson
- Jonathan Harris as Dr. Zachary Smith
- Bob May as The Robot (uncredited)
- Dick Tufeld as The Robot (voice) (uncredited)
- "You bumbling birdbrain!"
- "You mechanical misery!"
- "You ferrous Frankenstein!"
- "Never fear, Smith is here!"
- "This mechanical misfit."
- "Oh, the pain. The pain."
- "You disreputable dunce!"
- "You arrogant automaton."
- "You mechanical murderer!"