This hunter species has come a long way. They are an offshoot of the line that led from reptiles to birds. And they were already clever, as birds are clever, before the impact. Their forelimbs are like fumbling clawed mittens, but they are dextrous with beak and toes. Their lean, whipcord bodies would be the terror of your filmgoers, if not for the dense feathery coats that fluff them out to twice their true size. These were evolved for display and now do sterling service as insulation. They work with leather, wood and stone, and some groups have a little metallurgy. We are in Britain now too, though a Britain currently shackled to Europe by a vast, exposed mass of land. Bronze tools and ornaments are traded from here all the way to the Siberian steppes, to the warm belt of the world where the glacial cold cannot reach, and past that to the frozen southern horn of Africa.

The ice ages we remember as gone these ten thousand years are in resurgence here. Perhaps it’s because these hunters never started burning the fossil wealth of their world for industry. Or maybe it’s some butterfly-wing foible of climate change, now come into its own. The sea levels are low enough to separate the Mediterranean from the Atlantic, and to virtually abolish the North Sea. All that water is locked in the glaciers that march forwards and back across the northern and southern latitudes of the world. It is a harsh Earth, but the crucible that forged our ancestors was no less so.

Except here there are no ape descendants, and the role of quick, big-brained maker, dreamer and talker belongs to the dinosaurs’ heirs. They hunt fish and game with spears and fire, and with tamed birds like savage archaeopteryx—simultaneously hawk and hound for them. They are masters of domestication, with a hundred different species of animal pressed into service for work, meat or raw materials. They paint representations of themselves and the important things of their world—on stones that they erect, on the walls of caves, on rolled canvases of hide. They love ornaments and shiny things; a human could tell instantly which members of any group were high status, chiefs and mystics. The latter’s role is to mediate between the known—in this harsh place of ice and blood and stone—and the unknown that dwells on the far side of sleep and stories.