Two cutting-edge scientists give 'birth' to a Neanderthal—the first to walk the earth for some 35,000 years—in order to attempt to answer these questions. Part 'normal' child, part science experiment, William’s 'parents' struggle with the best way to raise him. As William grows toward adulthood, he is educated in the human experiences of love and intimacy. But his primitive impulses begin to emerge the more he tries to conform to human expectations, leading to tragic consequences for him and his loved ones.