Eventually, the narrative reveals Alanna's background. The novel is set in the indeterminate future, sometime after the events that Butler would later describe in her novel "Clay's Ark" and before the events of "Patternmaster". At the time of "Survivor", humanity is threatened by the "Clayark plague," an extraterrestrial disease that has destroyed half of the Earth's population, either by killing them or by mutating them and their children into the bestial "Clayarks." Humanity survives in an embattled state, supported somewhat by the "Patternists," a group of mutant humans previously living in secret. (The development of the Patternists is described in more detail in "Wild Seed" and "Mind of My Mind", and a later stage of their conflict against the Clayarks is described in "Patternmaster".)