Constantinople, 1883. Edith, the adopted daughter of the French ambassador, is interested of the past of the butler Jean and writes down the reminiscences of the Paris Commune. During an outing to the Black Island she chances upon the convicts working here. Rocks are blown up and one of the convicts, Kalin the Eagle, saves her from the falling pieces. She learns that he is Bulgarian revolutionary, not yet released although five years have elapsed since the liberation of country from Otoman domination. With her help Kalin the Eagle escapes and returns to Bulgaria.There he finds a new breed of plunderers in power. The veteran revolutionary, a participant in the April Uprising of 1876, is drawn to the socialists - the continuer's of his ideas. Edith finds out that the escaped convict is in fact her father, and sets out in search of him. Kalin, who is a danger to Bulgaria'new rulers, is murdered by a hired assassin. Edith arrives oh the day of his funeral which grows into demonstration.