Adam discovers that every human carries the entire story of life on earth hidden in his or her DNA and sees how we are all linked directly to the origins of life and to the first creatures with backbones. He also investigates the implications of the fact that for much of its existence, the human race was an endangered species.

Adam shows how decoding the genome has led us to begin to understand the very process by which our DNA makes us different; how it makes each one of us on earth unique and influences who we are and the traits we have. He reveals how, as we try and understand the relationship between who we are and our genes, we stand at the beginning of the most exciting scientific journey of all time.