40,000 years in the past, the last family of Neanderthals roams the earth. After a crushingly hard winter, their numbers are low, but Girl, the oldest daughter, is just coming of age and her family is determined to travel to the annual meeting place and find Girl a mate. However, through hunting accidents, animal attacks, old age, and disease, their numbers dwindle until Girl is left alone to care for Runt, a foundling of unknown origin. As Girl and Runt face starvation in the coming winter storms, Girl realizes she has one final chance to save her people, even if it means sacrificing a part of herself. In the modern day, archaeologist Rosamund Gale works well into her pregnancy, racing to excavate newly found artifacts Neanderthal before her baby comes. Linked over the millennia by their shared experience of early motherhood, both stories examine the often taboo corners of women's lives.