Beyond the Burn Line

It's two hundred thousand years in the future. Humanity is extinct, the ruins of its cities fossilised beneath sediments deposited by rising oceans. After a civilisation of intelligent bears collapsed when a plague turned them into crazed killers, their former slaves, descendants of racoons who call themselves the people and worship Mother Earth, have driven the last of the former masters northward and built a new civilisation. Peaceful and emphasising harmony with nature and cooperation between its tribes, but with strict divisions between the roles of men and women, it spans the American continent and is beginning to explore the rest of the world. But now, sightings of mysterious visitors are being reported. Are they bears which escaped the plague, a remnant population of human beings, or an unknown intelligent species? Where are they from, and what do they want?