Shadow's End

ALLIANCE CENTRAL: the world once called Earth. Nothing breathes upon it but man and the wind, and the wind is tamed beneath great domes. From here humanity rules a vast stellar empire. FIRSTISM: the belief that the universe is made for humanity. Therefore be fruitful, and multiply, and replace all other creatures with humankind and its domesticated beasts, and replace all other green things with plants useful to human life...
HERMES SECTOR: the remote frontier system where colonists are abruptly wiped out by an alien visitation. As a deadly threat to the countless billions of humans swarming outward from Alliance Central, the aliens must be identified. One planet alone in Hermes Sector was spared. But that planet is Dinadh, the strangest and most secretive of all populated worlds. Firsters are not welcome on Dinadh, nor Firster technology.
The only people from Alliance Central qualified by blood to visit Dinadh are a lone woman and her severely disabled five-year-old son. Their journey to Dinadh marks the beginning of a terrifying ordeal pitching mother and son beyond the shadow cast by human civilization. Astounding sights, extraordinary aliens and colossal dangers await them...