1656. Before the Thirty Years War ended, a new one began - "all against all." Russia is introducing troops into Poland at the same time fighting Sweden. The Elector of Brandenburg, a vassal of the Polish crown, strives to come under the protection of the Swedish king Charles and insists that his relative, Duke of Courland Jacob Kettler, do the same. But Kettler is negotiating Russian citizenship. Cardinal Mazarin of France sends two scouts disguised as jogger nuns to Courland. Their task is to captivate Duke Jacob and convey to him the secret message of the cardinal. And Tsar Alexei Mikhailovich sends a delegation to the duke, including the clerk of the Ambassadorial order Arseny Shumilov, with the task: to prepare negotiations on the lease of the Courland seaports...