After the Avais project the Red Star was knocked off course, there was no more threat of thread. The dragon riders kept protecting Pern even though the Holders thought that it was unnecessary. The Weyrs shrunk after a while and they consolidated into only four Weyrs. On the northern continent Fort Weyr, Igen Weyr, and Telgar Weyr. On the southern continent Southern Weyr stayed strong. Out of a slight suspicion after 200 years dragon riders watched for the Red Star but it did not come. There was a since of relief all around Pern the tread was gone. A few still suspicious riders still watched the night sky and fifty years later they were rewarded. A red dot was in the night sky and getting large. Thread was coming again. Some still did not believe but were proven wrong by the growing Red Star in the sky. The four Weyrs prepared. They made an arrangement to have the three north Weyrs all come to where the thread would fall. All the while the Red Star approached.