For thirty years, an expedition to the hellish desert planet V9-Gamma was stranded, and the people had no choice but to begin their own small settlement there. The colony's survival was maintained by William Benteen (James Whitmore), a charismatic leader who believes that this strict discipline prevents them from giving up hope in the harsh, unyielding environment. When a rescue mission from Earth finally arrives, Benteen is at first as jubilant as the others, but then he sees his power and influence begin to diminish. When he realizes that the colonists do not want to stay in a group on their return to Earth, he tries to persuade them to stay. Everyone else chooses to return home, but Benteen announces that he will remain behind alone if he must.
On Thursday, the people board the ship, the rescue mission's Colonel Sloane and the colonist Al Baines, search for Benteen to give him one last chance to change his mind, but he is nowhere to be found. After they give up and leave, Benteen emerges from the top of the cave that had sheltered his people. As the ship prepares for takeoff, Benteen talks to his people as if they are still there. Then, remembering the beauty of Earth, he realizes that he is alone and wants to go home. He rushes out screaming for the ship to come back, but it is too late. He is now stranded on V9-Gamma for the rest of his life, completely alone in the barren, lifeless deserts.
On Thursday, We Leave For Tropes:
- Accentuate the Negative: Benteen tries to convince the other colonists not to leave by playing up Earth's negative qualities, portraying it as a complete hellhole. In the end, the only person he's able to convince is himself.
- The Aloner: How Benteen ends up.
- Binary Suns: V9-Gamma's star system has two suns. As a result, the planet experiences Endless Daytime. A young boy named Jo-Jo has no concept of what night is.
- Bittersweet Ending: The colonists escape, but Benteen is left all alone, pleading to go back to Earth.
- Commander Contrarian: Al Baines is this in the beginning for Benteen. Years of living on the planet made him pessimistic and frustrated with Benteen's optimism while the latter kept trying to keep everyone's spirits up and be the voice of reason. Ironically, when Benteen became more unhinged, it was Baines himself who tried to be the voice of reason in the end.
- Commune: In order to keep control over "his" people once they return to Earth, Benteen intends to obtain a land grant from the US government so they can set up their own community isolated from the outside world. He takes it for granted that the other survivors will follow him unquestionably. However, when Colonel Sloane advises him to discuss the matter with them, Benteen discovers that they all intend to go their separate way and settle in different states. Benteen is devastated.
- Control Freak: Benteen became this sometime during the survival.
- Death from Above: The survivors are forced to take shelter from a meteor storm in a large cavern after the funeral of the woman who committed suicide. The rescue ship Galaxy 6 arrives as soon as the storm is over.
- Driven to Suicide: Nine people have committed suicide in the last six months in order to escape the hellish conditions of V9-Gamma.
- Fatal Flaw: Benteen's stubbornness and need for control.
- A God Am I: Sloane sees Benteen as believing this.
- Hero Antagonist: Colonel Sloane.
- His Own Worst Enemy: Benteen. His stubbornness and desire for control is his downfall.
- Sanity Slippage: Benteen starts to lose it after it becomes clear that he's lost control over the colonists. First, he tries to wreck the ship by attacking it with a pipe. Then after everyone else goes to leave, he hides himself away in the caves and talks to the now-absent colonists. He snaps out of it towards the end and realizes that he doesn't actually want to stay behind, but by that point, it was too late.
- Single-Biome Planet: V9-Gamma is a desert planet because its two suns shine perpetually.
- Survival Mantra: Benteen instructs "his" people to chant "There's a ship coming!" in order to maintain a spirit of hope after Al Baines raises doubts in their minds.
- Tragic Hero: Benteen. His stubbornness kept himself and the colonists alive, and then it marooned him on the planet.
- Tuckerization: Captain William Benteen is named after Captain Frederick William Benteen, who fought in the Battle of Little Bighorn. The real Benteen is mentioned several times in "The 7th Is Made Up of Phantoms".
- 20 Minutes into the Future: The Earth ship Pilgrim I containing 113 people landed on the planet V9-Gamma in August 1991. A rescue ship, the Galaxy 6, arrives to bring the impoverished survivors back to Earth in 2021.
- Wasteland Elder: Benteen has done all he can to keep the colonists together and keep their hope for rescue alive, but it's Subverted when Sloane arrives and provides an escape from the wasteland and Benteen is less than willing to give up his role as a leader. He'd rather keep them on the desert planet, barely scraping out an existence and forever looking to him for guidance, than go back to Earth where they won't need him.