This is the story of a Polish family during the Second World War and immediately afterwards. Joseph Balicki is the headmaster of a primary school in Warsaw; his wife is Swiss, and their three children, Ruth, Edek and Bronia, are 13, 11 and 3 years old when Joseph is arrested by the Nazis in 1940. Soon afterwards his wife is taken to forced labour in Germany, and his house is blown up. The children escape over the roofs before the explosion and join the gangs of orphans living in the ruins of the bombed city, existing as best they can. The 'silver sword' is only a paper-knife, but it is the talisman that, after the Germans have been driven out of Warsaw, gives Ruth, Edek and Bronia the hope and courage to make an astonishing journey across Europe. Accompanied by their friend, the fierce and resourceful Jan, they reach a refugee camp on the shores of Lake Constance and are reunited with their parents.