The film version of the four-part docudrama, shot on the occasion of the 1150th anniversary of the arrival of the Slavic heralds, focuses on their work in Great Moravia. At the beginning of the historical reconstruction, created on the basis of preserved period reports and legends, the elderly Methodius recalls his mission with his younger brother Constantine (Cyril). At the request of Prince Rostislav, the Byzantine Emperor Michael III sent in 863. both scholars from Constantinople to Great Moravia spread the ideas of Christianity. The Thessalonian brothers, who brought the first Slavic script to the country but encountered pagan customs and, above all, opposition from the Frankish priests.