The main character is a commander of a nuclear powered submarine. Once a very promising hydroacoustics expert, he sacrificed his scientific career to devoting himself to serving his homeland as a warrior. Gradually, he figures out that the worth of mastering the art of war is in its non-appliance.
The film takes us back into the times of the Second Bulgarian Kingdom - 13th century. The Bulgarian Emperor - Tsar Ioan Assen - is trying through several marriages to enlarge the State and to support the peace in it.
Earth shakes from the anger of the Zmei. Raven must find a new cook for his master. On Earth he finds Veselinov - a musician and an artist, father of Nadia.
