In 1994, a thirteen year old boy disappeared from San Antonio, Texas. Three and a half years later, he is found alive and well thousands of miles away in a village in southern Spain with a story of kidnapping and torture. His family is overjoyed to bring him home. But all is not quite as it seems. The boy bears many of the same distinguishing marks he always had, but why does he now have a strange accent? Why does he look so different? Any why doesn't the family seem to notice these glaring inconsistencies? It's only when an investigator starts asking questions that this strange tale takes an even stranger turn.
Dr Alice Roberts re-traces the greatest ever journey taken by our ancestors. Thousands of years ago one small group of our species, Homo sapiens, crossed out of Africa and into the unknown. Their descendants faced baking deserts, sweat-soaked jungles and frozen wildernesses and risked everything on the vast empty ocean. Within 60,000 years they colonised the whole world... How did they do it? Why do we, their descendants all look so different?
Alice Roberts tries to find out how Stone Age people reached North and South America for the first time. She finds out about an ancient corridor through the Canadian ice sheet that might have allowed the first humans through. Old finds in Chile though point to a whole different route for the first humans making it there.
The journey continues into Asia, the world's greatest land mass, in a quest to discover how early hunter-gatherers managed to survive in one of the most inhospitable places on earth - the Arctic region of Northern Siberia. Alice also explores what may have occurred during human migration to produce Chinese physical characteristics, and considers a controversial claim about Chinese evolution: that the Chinese do not share the same African ancestry as other peoples.
Dr Alice Roberts looks at our ancestors' seemingly impossible journey to Australia. Miraculously preserved footprints and very old human fossils buried in the outback suggest a mystery: that humans reached Australia almost before anywhere else. How could they have travelled so far from Africa, crossing the open sea on the way, and do it thousands of years before they made it to Europe? The evidence trail is faint and difficult to pick up, but Alice takes on the challenge. In India, new discoveries among the debris of a super volcano hint that our species started the journey much earlier than previously thought, while in Malaysia, genetics points to an ancient trail still detectable in the DNA of tribes today.
Alice travels deep into the Asian rainforests in search of the first cavemen of Borneo and tests out a Stone Age raft to see whether sea travel would have been possible thousands of years ago, before coming to a powerful conclusion.
When our species first arrived in Europe, the peak of the Ice Age was approaching and the continent was already crawling with a rival: stronger, at home in the cold and even (contrary to their popular image) brainier than us. So how did the European pioneers survive first the Neanderthals and then the deep freeze as they pushed across the continent? Alice Roberts reconstructs the head of the 'first European' to come face to face with one of our ancestors; she discovers how art became crucial for survival in the face of Neanderthal competition; and what happened to change the skin colour of these European pioneers from black to white.
The boy bears many of the same distinguishing marks he always had, but why does he now have a strange accent? Why does he look so different? Any why doesn't the family seem to notice these glaring inconsistencies? It's only when an investigator starts asking questions that this strange tale takes an even stranger turn.