Great sky river

From back cover Warner paperback August 2004: Nearly 100,000 years after first contact with the machines that dominate the universe, only a few hundred humans survive. Trapped on Snowglade, a barren world near the center of the galaxy, Killeen and his child Toby of the Bishop Tribe are primitive scavengers, homeless and hunted by the ruling "mechs." Then suddenly, a strange cosmic entity -- n...