Nuclear-apocalypse survivor Ann Burden lives an agrarian life on her family's valley farmstead, sheltered from radioactive contaminants by rocky hillsides, favorable weather patterns, and an abundant ground-fed water supply. One day, Ann encounters refugee John Loomis. He claims to be an engineer, who, aided by medicines and a radiation suit, walked from a distant government bunker to Ann's valley. Loomis bathes in contaminated water, and immediately sickens, but is nursed back to health by Ann, who welcomes him into her farmhouse.

Loomis regains his strength, and gradually, becomes part of Ann's humble rustic life. He helps Ann pump diesel from local petroleum pumps and gets the farm's long-disused tractor running to expand her gardens for the winter.