After two hundred years of peace something on Pern is shifting - changing weather patterns and volcanic eruptions herald the second Pass of Thread, the hideous scourge that threatens all life on the planet.

As the Weyrs and Holds prepare for the first pass since the loss of Landing and the knowledge of their ancestors one Lord Holder is refusing to co-operate - denying the existing in thread and damning his people to ignorance and, ultimately, death.

With the first fall on the horizon, his fellow Weyrleaders and Lord Holders must find a way to bring him into line and make sure the planet is safe.