Ours not to ponder what were fair in Life,
But, finding what may be,
Make it fair up to our means.

When Mankind first discovered Pern, third planet of the sun Rukbat, in the Sagittarian Sector, they paid little attention to the eccentric orbit of another satellite in the system.

Settling the new planet, adjusting to its differences, the colonists spread out across the southern, most hospitable continent. Then disaster struck in the form of a rain of mycorrhizoid organisms, which voraciously devoured all but stone, metal, and water. The initial losses were staggering. But fortunately for the young colony, "Thread," as the settlers called the devastating showers, was not entirely invincible: both water and fire would destroy the menace on contact.

Using their old-world ingenuity and genetic engineering, the settlers altered an indigenous life-form that resembled the dragons of legend. Telepathically bonded with a human at birth, these enormous creatures became Pern's most effective weapon against Thread. Able to chew and digest a phosphine-bearing rock, the dragons could literally breathe fire and sear the airborne Thread before it could reach the ground. Able not only to fly but to teleport as well, the dragons could maneuver quickly to avoid injury during their battles with Thread. And their telepathic communication enabled them to work with their riders and with each other to form extremely efficient fighting units -- wings.

Being a dragonrider required special talents and complete dedication. Thus the dragonriders became a separate group, set apart from those who held land against the depredations of Thread, or those whose craft skills produced other necessities of life in their crafthalls.

Over the centuries, the settlers forgot their origins in their struggle to survive against Thread, which fell across the land whenever the Red Star's eccentric orbit coincided with Pern's. There were long Intervals, too, when no Thread ravaged the land, when the dragonriders in their Weyrs kept faith with their mighty friends until they would be needed once more to protect the people they were pledged to serve.

After one such long Interval, when Thread renewed its violence, the dragonriders were down to one single Weyr: Benden. Its courageous Weyrwoman, Lessa, rider of the only gold queen, Ramoth, discovering that dragons could move through time as well as space, took a desperate gamble and flew four hundred Turns into the past to bring the other five Weyrs forward in time to renew the defense of Pern.

Circumstances encouraged exploration of the southern continent and there Lord Jaxom, rider of white Ruth; his friend, F'lessan, rider of bronze Golanth; Journeywoman Jancis from the MasterSmithcrafthall; and Piemur, Harper at large, discovered the most important artifact in the settlers' original Landing: AIVAS -- Artificial Intelligence Voice Address System.

With the myriad files of information that the colonists had brought with them, Aivas was able to restore lost pieces of information for all the Crafthalls. He was also able to teach them how to rid their world of the cyclical dangers of the erratic satellite, inaccurately called the Red Star.

F'lar and Lessa, Benden's courageous and far-seeing Weyrleaders, were the first to encourage Lord Holders and Craftmasters to end the domination of Thread and start a new era on Pern. Almost all Lord Holders and Craftmasters agreed, especially since Aivas could provide them with new methods and technologies for improving health and quality of life.

Those who considered Aivas an "abomination" attempted to stop the splendid project, but were defeated. Instructed and trained by Aivas, the young riders and technicians were able to transport, by means of the dragons, the antimatter engines of the three colony ships -- still in orbit above Landing -- and place them in a massive fault on the Red Star. The subsequent explosion was visible from much of the planet, and people rejoiced to think they would finally be rid of Thread.

Now, though, Thread continues to fall, because the swarm already brought in by the Red Star has not yet completely passed by Pern. Dragonriders and harpers have explained to those who would listen that this Pass is the last one Pern will have to endure.

They must now start planning for a Threadfree future, making use of the Aivas files, full of helpful but not overly sophisticated technology that will improve life for everyone on Pern. Even the dragonriders, for centuries the defenders of Pern, must fit themselves for new occupations. The questions are: Which technologies can be adopted without disrupting the culture of the planet? And how will the dragonriders integrate themselves and their splendid friends into the new Threadfree society?