Thread: deadly silver strands that fall from the sky like rain, devouring every organic thing in their path - animals, plants, and people alike. Who could believe that such a horrible thing could exist? After all, it's been two hundred years since Thread supposedly fell on Pern. No one alive remembers that first onslaught. There's no sign of it anywhere in the world. Only the dragons, originally created to be a weapon against Thread, are still around to remind people that once before their population was decimated, their hopes and dreams and livelihoods almost destroyed forever.