A university professor's translation of prehistoric drawings found in an Ozark Mountain cave relates a thirty-thousand-year-old story from the Pleistocene Period. Neanderthal teenage sisters, CAY and FLO, aided by ravens, leave their dying tropical island home searching for a safe haven for their tribe who face imminent starvation. Their search takes them by log raft across a perilous sea to the continent where they find mutant humans and animals at every turn, as they hike across arid plains, tropical jungles, mountain ranges, and slog across a vast swamp. Humans, animals, and fowl provide unexpected aid. Fighting great odds, they find a new homeland, but must return across the sea, to their island home, and rescue their people. For one sister, it is too late. She returns in spirit as a white raven.