Don and Judy are on a mission to set up a new communications relay along with Will and Dr. Smith. The project seems to be going quite well until Dr. Smith brings it down with a skeet shot. Don is very angry and orders Smith to clean the mess up. Will kindly volunteers to help with the job and when they begin to clear away the debris they find a young woman frozen in a large block of ice.
Since no one knows if the girl is peaceful or hostile, Don decides that the block of ice should be guarded. He orders Smith to maintain a strict watch all night. During his shift Smith gets cold, bored. and tired. He decides to drink some coffee and take a nap. Since he does not want the Robot to tattle on him, Smith takes out his power pack and goes to sleep. Foolishly, he leaves his electric blanket on top of the block of ice, which causes the ice to melt and the young woman to wake up.
Later, Don gets up and finds Smith sleeping. When they check the cave and discover that the girl is gone, they follow her tracks. When they encounter her, they discover that she is a beautiful Ice Princess. She means them no harm, but she seems to be terribly frightened about something. Although she cannot speak, she understands them and they promise to keep her safe.
When an alien spacecraft lands nearby, the Ice Princess becomes even more afraid. The Robot goes to investigate and he meets a silver-skinned alien named Chavo. Chavo asks the Robot about the Ice Princess, but Robot refuses to answer. In order to loosen the Robot's tongue, Chavo pours tequila into his sensors and makes the Robot extremely drunk.
The drunken Robot stumbles back to camp singing and passes out. Dr. Smith and Will take care of him, and the Robot ashamedly admits that he may have told Chavo they were hiding the Ice Princess.
Will goes to visit Chavo for himself and Chavo tries to convince the boy that the Princess’s parents sent him to rescue her. Will doesn’t believe a word of it and deduces that Chavo really intends to hold the woman hostage for ransom money. Chavo then decides to make Will his hostage.
Chavo goes to camp and confronts Don and Judy. He informs them that he will release Will only when they have released the Ice Princess into his care. Don and Smith go to Chavo’s camp and try to rescue Will, but it appears that Chavo has the place too well guarded so they retreat. When they arrive back at camp, Judy tells them that the Ice Princess has disappeared.
The Robot and Dr. Smith come up with their own plan to rescue Will. They construct a fake princess and take her to Chavo’s campsite to make a prisoner swap. The trick fools Chavo at first and he lets Will go, but when Chavo discovers it is not the real Ice Princess he gets very angry.
Chavo fights with Don and beats him up. Chavo then attempts to do battle with the Robot bull-fight style, but the Robot bests him. Chavo feels shamed by his defeat and decides to retire. He gives up his kidnapping plans and leaves. Moments later, the Ice Princess appears long enough to transport herself back to her own world.
- The Jupiter 2 does not appear in this episode.
- During its syndicated run, this episode was banned by several Los Angeles television stations due to the portrayal of Chavo.
- Why was the episode titled “Castles in Space” when there weren’t any castles?
- Why would having tequila poured into him make the Robot drunk?
- If he was trying to be inconspicuous, why was Chavo carrying his own “Wanted Poster” around in his pocket?
- Robot claims that when he saw the Fake Princess, he thought for a moment that it was the real girl. The dummy looks absolutely nothing like the Ice Princess!
- Judy tells Don that Will is “sleeping like a baby.” However, mere moments later, we see Will singing and playing his guitar.
- When first computing the Ice Princess, Robot says she cannot speak because her vocal chords will not function in their planet’s atmosphere. At the end of the episode though, she speaks loudly and clearly to summon herself home.
- If the Ice Princess was able to simply transport herself back to her own planet on command, why didn’t she do so as soon as she woke up?
- The Ice Princess is played by Corinna Tsopei, Miss Universe 1964. Ironic, huh?