The first program tells the story of the conquest in 1519-21 of the Aztec empire in Mexico by Hernan Cortes and 500 Spanish conquistadors. Michael Wood follows the path of gambler and womanizer Cortes from his home in Spain to the Mayan pyramids on the shores of the Yucatan, on through the tropical forests of Tabasco to the snow-capped volcanoes of Mexico.

Six years after the fall of Mexico, the conquistador Francisco Pizarro, exploring south of the equator, uncovers another civilization unknown to the European world: the empire of the Incas, which extended 3,000 miles from Ecuador to Chile. Michael Wood recounts Pizarro's daring march into Peru with fewer than 200 men and tells the almost incredible tale of his capture of the Inca Atuahuallpa and his promise to ransom himself with a roomful of gold.

Episode three begins in Quito, Ecuador, and relates the amazing story of the 16-month Spanish expedition (1541-42), led by Gonzalo Pizarro, to find El Dorado, the mythical land of gold. Crossing the Andes with pack animals, Wood and his team hack a path through the forests, following in Pizarro's footsteps to the Coca river, where they build a balsa raft and sail down to the river Napo, following the route of the conquistadors. There, on Christmas day 1541, the Spanish expedition split, with 60 men under Francisco Orellana sailing (contrary to orders) all the way down the Amazon to the sea in a makeshift boat: an achievement that was "less of a journey, more of a miracle."

In the last segment, the story shifts to the North American continent. In April 1528, 400 conquistadors, dreaming of gold, land in Florida to begin the exploration and conquest of what is now the southern United States. After terrible months of trekking northward, fighting off hostile Indians in the swamps of Florida, they build boats and try to escape to Mexico. Most are never seen again. This is the tale of four survivors shipwrecked on the shores of Texas and in particular that of Alvar Nuñez Cabeza de Vaca, who wrote it all down many years later. Living among the Indians of the coast for five years, Cabeza de Vaca finally rejoins the three others; together they embark on an epic walk across America to the Pacific coast, reappearing in Mexico eight years after they were lost.