The plot of the novel takes place in the 9th century at the time of the brothers Constantine (Cyril) and Methodius from Salonica. The central figure of the novel is Constantine the Philosopher, the creator of a new Glagolitic alphabet composed of characters having both numeric and symbolic value. Constantine found the inspiration for Glagolitic letters in the Mill Game that he had played since his childhood all around... In the same way as Constantine's application of rosette pattern and its various line drawings in his creation of Glagolitic letters confirms the importance of combinatory skill, so does the novel as a whole, which has been structured taking into consideration numerical values of Glagolitic letters and numbered accordingly, confirm the importance of game as such.
The plot of the novel takes place in Istanbul, Kerson, Moravia, Dalmatia, Venice and Rome. Constantine's life story is introduced from different perspectives and in different ways by four narrators (Methodius, Empress Theodora, Anastasius the Librarian and the Croatian prince Mutimir).