For two hundred years there had been peace on Pern - but now the signs were ominous. Violent weather storms and erupting volcanos heralded the coming of the second Pass of Thread, when the red planet would rain down its horrifying harvest which destroyed every living organism on the face of Pern. No human or dragon or animal or plant was safe from the hideous death inflicted by Thread. Weyrs and Holds tried to prepare, but they had serious problems. Over the generations much of the old technology had been lost. AIVAS, the giant information bank, was buried under tons of volcanic ash, and valuable and skilled men and women had succumbed to disease and old age, taking with them the knowledge of a great civilization. They had to prepare as best they could, training the great flights of dragons and ensuring that the Lord Holders did their part by protecting their people in every possible way. Only Lord Chalkin, Holder of Bitra, refused to co-operate. He did not believe in Threadfall.