To retell the life story of St. Agnes the author was forced by the question of what led the daughter of the Czech king Přemysl Otakar II, whose hand the emperor himself asked for, to decide to renounce worldly power, carnal love and become a nun. The story that The Secret tells stands on the ground plan of preserved historical facts. He sees the 13th century as a period of conflicting power and spiritual currents, in the center of which Agnes stands: first as a lonely child wandering around European courts, later as a girl, with her head confused by knightly myths, betrayed and yet yearning for love and fulfillment - but also a girl aware of her own responsibility - towards her family and country. Perhaps her life hid a secret that Christian legends would not allow to be told.