I died as a respected professor of anthropology, but woke up in the body of an unnamed young man in the middle of a tundra steppe, surrounded by cave hyenas. All around—there is a harsh, primordial world of the last Ice Age. And in my head—lies the entire future story of humankind: its breakthroughs, its dead ends. But no matter what knowledge I possess, it is the spear and instinct that rule here. And if I am to be heard, I must first earn my place by the fire. Only then will I be able to begin my real work: step by step, unnoticed by those around me, I will change the course of an entire species.