Our contemporary, a 29-year-old surgeon Nikita Saveliev, gets caught in the “Nevsky Express” disaster and finds himself in medieval Rus, in the era of Tsar Alexei Mikhailovich’s reign. It’s hard to survive without money, housing, and work, without friends. But Nikita survived—more than that—he saved the Tsar, and otherwise the fate of the state could have turned out differently.