Klousios, according to the most probable hypothesis, is the ancient name of the river Oglio. The film follows its flow in order to present the evolution of the prehistoric cultures in the plain south of the province of Brescia (Italy). Beginning with the glaciers and the Paleolithic finds on the rocky hills of Montichiari and Capriano, we move through the Neolithic discoveries of Isorella, Manerbio and Piadena. The early Age of Bronze is documented by the site of Remedello Sotto and its links with the Similaun man and the culture of the Campaniform Gobelet. The Bronze Age is illustrated by numerous sites and the beginnings of the plain’s deforestation. The Etruscan presence marks the Age of Iron, and the arrival of the Celtic tribe of the Cenomanes, with their splendid silver objects, brings the film to its close.