While out walking, Penny and Dr. Smith find a strange spacecraft with someone inside. Penny greets the visitor, but he responds rudely and threatens them. Although Smith wants to leave immediately, Penny berates the alien for his lack of manners, but when the alien fires on them, they flee back to the Jupiter 2.
Maureen is in command while John and Don are away and uses the force field to protect the camp. They notice a second spacecraft arrive, and shortly after discover a large gift of luxuries in front of the Jupiter 2. A golden alien appears and introduces himself as Keema. He explains that he and the alien Smith and Penny met are representatives of their home worlds. They intend to fight a war on the planet, and Keema ingratiates himself with the Robinsons to gain their support.
Penny is the least trusting of Keema’s story, and Maureen agrees that there are two sides to every story. The other alien, though, refuses to speak of his mission. Keema returns and asks the Robinsons for the use of their weapons, for which favour he will return them to Earth when the war is over. Maureen refuses, and the Robot goes to Keema’s camp to investigate his motives. He finds that Keema has been lying to the Robinsons, but is severely damaged and unable to report back.
The next day Judy is rescued from a minefield by Keema, who blames the other alien for planting it. Penny runs to the other alien’s ship to ask if he was indeed responsible; he reveals himself to her—he is an ugly little frog-like creature—and he tells her that he had nothing to do with it. He accompanies Penny back to the Jupiter 2 where they meet Keema and an argument ensues. With war inevitable, Smith secretly takes the Robinsons’ weapons to Keema only to discover him in his hideous natural form. Keema reveals his deception to Smith who flees back to the Jupiter 2.
The war begins, and despite the danger Penny goes to her friend’s ship to see if he is all right. She finds him injured and insists on helping him despite the escalation of Keema’s bombardment and the alien’s repeated requests for her to return to safety. When Keema appears to kill his opponent, the frog-like alien manages to let off a final volley that destroys Keema.
As the alien prepares to leave, he transforms himself into a handsome man so that Penny will have fond memories of him. Penny demurs, saying that it wasn’t necessary… they were already friends.
- Basically the episode is a lesson about prejudice as the ugly frog alien is really the good guy and the handsome golden man is the villain.
- A working title for the episode was "Twinkle, Twinkle, Little War."
- The revised final script is dated October 17, 1966.
- The original script called for Keema to turn into a werewolf at the end of the episode. However, CBS felt that this would scare children watching the show and it was dropped.
- Once the war is over, and Penny’s friend is saved, why doesn’t he help the Robinsons by giving them passage back to Earth?
- When carrying Judy out of the minefield, Keema bumps his foot against one of the mines. Luckily for him and Judy it doesn’t explode...
- This episode made use of a number of silly props! The barbed wire fence had Christmas lights all over it, all the scary landmines were beach-balls, and Keema made his transmissions through a turkey baster.
- A very confusing moment happens at the end of the episode. Penny runs out in the middle of the war to help her “little alien” friend. She finds him lying on the ground, near death. He tells her it is too late to help him, and Smith also says that there is nothing that can be done. However, a couple of minutes later, after Keema is destroyed, the “little alien” quits dying and gets up, apparently fine again.