Astronaut Warren Marcusson and scientist Sam Conrad are watching as their two-man spaceship is prepared for the flight to Mars in three hours. Marcusson wonders why they are there rather than out seeing on Earth on what may be their last night there. Sam wonders if Marcusson is afraid, and admits that he's afraid of the unknown. Marcusson shares his personal philosophy: people are alike all over. Whoever they meet on Mars, they will be just like them.
The expedition proceeds but the spaceship crashes on Mars. Marcusson is badly injured in the crash and Sam does what he can for him. They hear a knocking noise on the hull but Sam refuses to open the door. When Marcusson wakes up, he discovers that Sam has yet to open the door. The scientist claims the door is jammed, but finally admits that he's afraid. Marcusson insists that the people outside are just like them, and he doesn't want to die within the ruined spaceship. Before he can get the door open, he dies of his wounds. Sam finally opens the door and finds a group of human-like Martians outside, quietly waiting for him.
Two males and a female step forward and gently relieve him of his gun, then speak to him in English. When Sam admits he's surprised to hear them speak English, one of the males explains that they've telepathically taught him their language. They confirm that Marcusson is dead and offer to let Sam get some rest. Sam is surprised to see that they are indeed just like humans. As they take out Marcusson's body and assure Sam they will bury it appropriately, the scientist admits to his dead friend that he was right and people are alike all over.
As the Martians take Sam back to his ship, he asks them questions about their civilization. They tell him that they'll answer his question in the morning when he's had some rest, and they'll prepare a place for him. As they go, Sam asks the female Martian what her name is. She introduces herself as Teenya and he thanks her for his help. When he expresses worries, she insistently tells him that no one on Mars will hurt him.
The next day, Teenya and the others arrive and tell Sam they have a surprise for him. He goes with the, noticing that Teenya seems reluctant to participate in the surprise. They take Sam to their city and lead him to a building. Inside is an exact replica of a suburban Earth home. The Martians inform him that they took all of the structures and decorations from his mind telepathically, and they want to make sure he's comfortable. They're very insistent on finding out that he finds everything to his taste. The Martians asks him to stay thee while they make arrangements to take him on a tour of the city. As they leave, Teenya hangs behind and Sam asks if he'll see her later. One of the males cuts her off and assures him that he will.
Sam explores his new home office and initially enjoys the creature comforts. However, he soon makes three discoveries: the gas stove doesn't work, there are no windows, and all the external doors are locked. Banging on the doors, he gets no response. Sam runs to the front drapes and pulls them down, and discovers a shuttered viewing port. It opens revealing bars… and a crowd of Martians viewing him on the other side. Sam realizes that he's in a zoo: an Earth creature in its native habitat. He looks out into the crowd and sees Teenya sorrowfully looking back at him. As she turns and runs away, Sam admits that Marcusson was right: people are alike all over.