Dragonsong takes place on the planet Pern, which was settled by colonists from Earth some centuries earlier. Like medieval society, Pern is divided into three interdependent estates: the Weyrs of the dragonriders; the Holds which shelter the majority of the population and produce crops and other basic resources; and the Crafts, where technical and artistic skills are practiced. The planet's ecology is very unlike Earth's.

Because of the erratic Red Star which orbits its sun, Pern is subject to periodic attacks of Threadfall—streams of spores falling into its atmosphere from the Red Star, which devour all organic matter they touch. The indigenous animal life is different too. Long ago genetic scientists from the colony ship bred huge sapient dragons from the native fire lizards. These dragons, with their ability to breathe out flame, form the primary defense against Threadfall. Perhaps because of this planetwide menace as...