In the midst of a war on Earth, a space station in New York sends a few colonists to establish a village on Mars. The Bittering family, (father Harry and mother Cora and their children Dan, Laura, and David), arrives as part of the few colonists chosen for the first wave. Harry is initially disquieted by the Martian environment, but they take comfort in the fact that the family can return to Earth when resupply ships arrive.
Strange events begin to affect the life brought as part of the settlement effort, including the seeded grass sprouting purple, the family cow growing a third horn in the middle of its head, and other anomalies with the vegetable garden. Harry's discomfort on Mars increases and the thought of returning to Earth on the next resupply mission soon becomes his only comfort, much to the concern of Cora. This comfort is taken away as Bittering is informed that the war has led to an atomic bomb devastating New York City and destroying the only spaceport capable of supporting travel to Mars. Resolving to build himself a rocket home, Harry isolates himself from his family and the townsfolk, who have begun to show signs of transforming into Martians as their limbs and bodies elongate, their irises become shimmery gold, their skin darkens. One night, Iorrt, the Martian word for Earth, comes into his head, even though he never learned it anywhere. Harry staves off the transformation as he only consumes food and water brought from Earth, but the supplies run out and he is forced to eat Martian food to survive. Soon enough, Harry notices his eyes have turned gold.