While out on a nature walk, Dr. Smith, Will and the Robot come across a strange keyhole shaped monolith beneath which sits a lyre on a pedestal. When Smith plays a few notes, he is transported to a fiery realm he believes to be hell. There he meets Morbus, whom be believes to be the devil. Morbus shows Smith his past misdeeds, and coerces him into destroying the lyre in return for passage out of Hades. Dr. Smith tries to destroy the lyre but is unable to do so.
Morbus later arrives at the Robinsons’ campsite where he is received cordially by all except Dr. Smith (who has not told anyone of his experience) and Don (who is suspicious of the stranger). Morbus prevents the Robot from revealing his identity as an alien by fusing his power pack and damaging his memory tapes.
Morbus and Judy go for a walk while, unbeknownst to them, Dr. Smith goes back to the monolith to destroy the lyre. The sound of the lyre is excruciatingly painful to Morbus, and in his attempt to escape, both he and Judy are transported to Hades. There Judy is inconsolable when Morbus tells her he is in fact an imprisoned revolutionary, and that there is no escape from his prison.
John and Don go to the monolith with Dr. Smith and the Robot. They have repaired the Robot and found out that Morbus is a dangerous alien. The Robot tells them that Judy can be returned by playing a certain chord on the lyre. When Smith attempts it, he is transported to Hades. Don and John follows him by having the Robot play back the chord. Once there, Don tries unsuccessfully to fight with Morbus, but Judy breaks the lyre by accidentally hitting Don with it when she tries to stop them fighting.
With the lyre destroyed, Morbus is free and his prison begins to fall apart. He is unrepentant and leaves for his home planet, sure that he will have success in a new revolution because he has now had millennia in which to plan it. Left alone by Morbus, Don, Smith and the Robinsons manage to escape back to the planet.
- This was the final network-aired Lost in Space episode on September 11th, 1968, being aired as a summer repeat following the series cancellation.
- The actor Gerald Mohr, who portrayed Morbus, died only eight weeks after this episode aired for the last time on network television.
- The costume of the creature in the cave was that of the Metaluna Mutant from the film This Island Earth and the gloves and claws were from The Creature from the Black Lagoon.
- Here is a link about Gerald Mohr: http://en.wikipedia.org/wiki/Gerald_Mohr
- As of this episode, and including the unaired pilot, "Lost In Space" was halfway through its run, with forty-two episodes down and forty-two to go.
- Gerald Mohr was an actor very familar to viewers of Saturday morning TV in the 1960s as the voice of Green Lantern in Filmation's cartoons and that of Reed Richards in Hanna-Barbera's "The Fantastic Four."
- When asked to where Dr. Smith has vanished, the Robot replies "to the place where the woodbine twineth", a phrase used by Mark Twain in "Life on the Mississippi."
- How did Morbus have access to Smith’s memories?
- Why wasn’t a child selected to play the child version of Smith? In the episode “Kidnapped in Space” when Smith accidentally reverts back into a little boy, a child plays him then... In this episode undoubtedly it was for the sake of campy humor.
- Isn’t Judy a little old to be throwing a temper tantrum?
- When Morbus goes over Smith’s ‘past misdeeds’, why was the sabotage of the Jupiter 2 not mentioned? Why was Smith’s attempts to kill the Robinsons not mentioned? Smith has done far, far worse things in his life than stealing cake!
- When Dr Smith plucks the lyre the first time, he is transported to Morbus' prison minus the musical instrument. The next time he does this, he is shown clutching the lyre.
- There seems to be no rhyme or reason as to whether plucking the lyre transports Smith to Hades or transports Morbus to the planet's surface.
- When Morbus shows Smith his youthful antics via the Intertemporal Projector, we see video of Zachary as a youth, except his real life grey hair can be seen sticking out of his cap!
- After the fight between Morbus and Don, Professor Robinson appears...from the OTHER SIDE of the prison bars! Shouldn't he have entered from the apartment door like everyone else?
- "How do we get out?" "Just follow me" says Morbus, as he exits the building stage right. John, Don and Judy lurch and rock 'n roll their way to the exit, as Morbus' prison begins to shake and crumble, but they turn left instead!
- The next scene shows them running for their lives as Morbus' prison disintegrates; the next minute, KABOOM! they are magically transported back to the planet's surface, hooray!
- Morbus: [dressed like Lucifer] "Well, Zachary, so you finally made it!" Dr Smith: "Good heavens" Morbus: "Hah ha ha, guess again!"
- Dr Smith: [stuck up a tree with the Robinsons attempting to extricate him] "Careful, I'm a sad faced widow" (I have no idea what that means...)