Dragon Riders of Pern (DRoP) is based onthe loved novels of Anne McCaffrey. Whilethere are numerous books in the series, theevents that follow will be limited to mostlythe first three: Dragonflight, Dragonquestand The White Dragon. It is set on the planet Pern. Society is divided out into groups: theHolders - basically, landowners with responsibility for their lands and people; Guilds - tradespeople and guild members(crafts and trades); and the Weyrs - dragonriders and their wonderful beasts.
It is the duty of the Holders to tithe to the Weyr that is beholden to them. In return,the Weyr protects the Hold from the scourge of Thread. Thread are spores that fall fromthe Red Star at intervals. They aredestructive; they will burn anything theytouch. Dragonfire and water are the onlythings that will stop them. It is wearing onman and dragon to fight Thread, leaving notime to plant and tend crops; hence the system of tithing.
Due to the erratic orbit of the Red Star, intervals occur where no Thread falls. When the story opens, it has been twice as long as normal since the last "Pass". People have forgotten the old teaching songs, warning of the dangers of Thread, and the responsibilities of all. There are those that feel that there are no more Threads, and thus dragons need to just go away. Support for the Weyrs has diminished.