If the Black Death of 1948 had killed three-quarters of the population of Europe instead of one-quarter – what would have happened to the world? Europe, weakened by such a catastrophe, would probably have been conquered by the Turks and the Americas would have remained in the hands of the Aztecs, Incas and other tribes. In this alternate world, 18 year-old Dan Beauchamp of New Istanbul (London) sets off the make his fortune in Mexico where the mighty Aztecs rule. When he arrives he hears that the nephew of King Moctezuma XII will reward followers who help him build a new empire and he joins the expedition to the Upper Hesperides, travelling in coal powered Aztec automobiles. When this mad venture turns out badly, Dan becomes involved in other glittering schemes for winning golden empires, bringing him many marvellous and funny adventures on the way.