The dragons of Pern are stricken by a mysterious fatal illness, and the young dragonrider Lorana finds clues to a cure in an old song. In the distant past, Wind Blossom, the scientist who bred the first dragons, understands that certain germs will someday become a plague that will kill them, but lacks the resources to prevent it. Five centuries apart, the two women become allies in a race against sickness and the destruction of all life on Pern.