A few years ago, Mark Adams made a strange discovery: Everything we know about the lost city of Atlantis comes from the work of one man, the Greek philosopher Plato. Then he made a second, stranger discovery: Amateur explorers are still actively searching for this sunken city all around the world, based entirely on the clues Plato left behind. Exposed to the Atlantis obsession, Adams decides to track down these people and determine why they believe it's possible to find the world's most famous lost city and whether any of their theories could prove or disprove its existence. He visits scientists who use cutting-edge technology to find legendary civilizations once thought to be fictional. He examines the numerical and musical codes hidden in Plato's writings, and with the help of some charismatic sleuths traces their roots back to Pythagoras, the sixth-century BC mathematician. He learns how ancient societies transmitted accounts of cataclysmic events, and how one might dig out the 'kernel of truth' in Plato's original tale.