The Tributary is an anthropology adventure set in the Amazon basin that looks to identify and pinpoint more accurately when mankind first arrived in South America. A scientific expedition hopes to achieve this through the discovery of a suspected, genetically-isolated tribe deep in the forest, from which DNA samples will enable them to illuminate a period of man's evolutionary history of which very little is known. It soon becomes clear, however, as they travel further into the depths of the jungle, that an even greater discovery beckons, a discovery that will have profound implications for the future of all mankind. The Tributary is a rendition on man's relationship with his blue pearly charge. It interweaves history, politics, science, religion, globalisation and climate change, and asks us to consider where we are going as a species: is it a glorious future for the human race, or one scourged with war, famine and drought? It links the Old World with the New and alludes, with the warning and prophetic words of an Indian chief: "Remember . . . bloodshed is the bedfellow of fear," to the horrors of its main protagonist's family history during the Spanish Civil War with the plight of indigenous populations during the Brazilian Military Junta of 1964-85.