One moment Conrad Schwartz was suffering from a severe hangover as he hiked through the mountains of present-day Poland, the next he was hurled back to the same country in the 13th century.

He remembered from his history classes that in another ten years, Mongol hordes were scheduled to attack, pillage, burn and kill—and Conrad was likely to suffer all of the above. So, he set out to turn Poland into a world power by introducing universal education, aircraft, radios, steamboats, and generally discourage Mongols or anybody else from messing with either Poland or Conrad. But things weren't going to be quite that simple. . . .