Once upon a time, during the era we now call the Pleistocene, somewhere between two and a half million and ten thousand years ago, small groups of people travelled around their known world, hunting for food, seeking shelter and slowly becoming more like the people we are today. 

In this book of few words, we see one very special young girl who seems to notice everything that happens around her as her people search for a cave to shelter in for the winter. She looks at the cave wall, picks up a stick - and afterward, everything was different.