When everything on Earth and in the universe seems already open and solved, scientists at the Institute of Fools’ Physical Theories announce that alongside ours exists a connected space where, side by side with our Earth, an entire mass of other Earths is invisibly present—each with its own history and geography.
Into one of those worlds a young scientist, Daniil Baturin, is sent—and he gets stuck there for a long time. In essence, the story could have gone another way: Caesar never crossed the Rubicon and embroidered crosses; America was discovered by drunken Etruscans, not Columbus; the people of the Drevlians killed Prince Igor and took over Kyiv; and the hordes of Genghis Khan never left their steppes. But people everywhere remain the same, and in all unpredictable worlds they make the same mistakes…