On the 150th anniversary of the publication of Darwin's famous On the Origin of Species, NOVA reveals answers to the riddles that Darwin couldn't explain. Stunning breakthroughs in a new science - nicknamed "evo devo" - are linking the enigma of origins to another of nature's great mysteries: the development of an embryo. To explore this exciting new idea, NOVA takes viewers on a journey from the Galapagos Islands to the Arctic, from the Cambrian explosion of animal forms half a billion years ago to the research labs of today. Here, scientists are finally beginning to crack nature's biggest secrets at the genetic level. And, as NOVA shows in this absorbing detective story, the results are confirming the brilliance of Darwin's insights, while exposing clues to life's breathtaking diversity in ways he could scarcely have imagined.