Second half of the 12th century. Yaroslav, the son of a powerful and warlike Galician prince, receives power after his father’s death, but immediately shows that he is not like his father in character. Yaroslav prefers diplomacy to slaughter. But is peacefulness a sign of weakness? At first it seems that Yaroslav will forever be obedient to his all-powerful father-in-law, Yuri Dolgoruky. Even Yaroslav’s wife is sure of this. And the young prince will have to prove the opposite to everyone and earn himself a worthy nickname - Osmomysl.