In the 19th century Switzerland, 14 year old Giorgio, like many other boys from very poor backgrounds, is sold to a slave trader and becomes a chimney-sweep in Italy. During the trip, as they cross the border, many drown to death. In Milan, however, Giorgio manages to contact a few other boys on the roofs of the city. Chased by the Wolves, a gang of young Milanese youths, the Swiss boys found The Black Brothers, a secret society which they can turn to for comfort and solidarity. Through this bond, they manage to regain their freedom and end up punishing the slave trader.