Crimea, 1787. Despite the Manifesto of the Russian Empress Catherine and the Kyuchuk-Kainarji peace treaty, which forever united Crimea with Russia, Europe continues to weave intrigues, trying to break this sacred union. In the undercover struggle, all methods were used - from shameless gossip, dark rumors and false articles in newspapers to dirty manipulations with the illegitimate son of the empress, sent to Europe for training - Alexei Bobrinsky, a passionate gambler and brawler. This weakness was cleverly exploited by international intriguers. Cut the knot of the conspiracy Catherine instructs true friends - midshipmen. Together with their fathers, their grown-up children, Shurka and Alexandra, go into battle.