A small boat reaches the shores of a raw and desolate landscape. A group of six have struggled across the narrow sea to find a new home. They are starving, desperate, and living 45,000 years ago. First they must find shelter, and they strike out across the tundra wastes towards the distant mountains that promise the abundant caves they need to survive. But when night falls, anticipation turns to fear and doubt as they realize they are not alone.