The Barkuu

A mysterious cloud is found in our solar system. When the cloud envelopes the planet, it litters Earth with metallic objects and lays waste to humanity's accomplishments. To avoid cataclysm people dig underground, burying anything important and fortifying systems. Upon emergence, we find the air cleansed and the planet recovering in a way not witnessed for centuries. Along with a network of metallic objects that emit ambient energies, we find communication satellites inexplicably intact. When the perpetrators of the cloud appear to claim their prize, they cull our numbers and reduce us to a natural species without resistance. The Barkuu, an ancient and calculating species, design bodies for Earth using us, and make it the latest in a vast network of planets. Hunted like game, and consumed like livestock; when subjugation by a truly advanced species is our only option, how will humanity fare?