The film "The Island of Rulers" presents the results of many years of research by archaeologists and other scientists on the origins of the Polish state. The creators used computer reconstructions to recreate the topography of Ostrów Lednicki from the 10th-11th centuries. The monuments discovered on the island and on the bottom of Lake Lednickie are shown. The most probable hypotheses concerning the construction of bridges in 963 and the invasion of the Czech prince Brzetyslav in 1039 were also presented. The film is completed with staging of fights and meetings between the Polish prince Mieszko I and the Czech princess Dobrawa, as well as the Polish king Boleslaw Chrobry and Emperor Otto III.