A battalion of Scottish mercenaries sent by Sweden to find the Abrabanels discover Grantville and quickly align themselves with the Americans, hoping to defend the village of Badenburg from an approaching division of Tilly's soldiers.

Mike leads the new U.S army to the nearby village of Jena, where they quickly defeat a legion of soldiers who broke off from Tilly's retreat and enticed the city into joining the new United States of Europe.

To fight this, Richelieu works with Albrecht von Wallenstein, head of the Holy Roman Empire's imperial army, to destroy Grantville, removing Sweden's main financial and logistical base in the continent.

Wallenstein sends a mediocre imperial division and directs a Spanish brigade to the towns of Suhl and Eisenach to distract the American army while a Croat mercenary force enters Grantville and massacres the population.

Mike and Rebecca sit down with Gustavus and decide to unite Sweden's German territories into the Confederated Principalities of Europe (CPoE) under the Swedish throne, though the U.S.E at its center is allowed to maintain its autonomy.

"[3] Kirkus Reviews called the book a "[s]inewy shoot-'em-up, with pikes and muzzle-loaders squared off against modern automatics and 20th-century tactics: a rollicking, good-natured, fact-based flight of fancy that should appeal to alternate-history buffs as well as military-fantasy fans.

When first contemplating a sequel, Flint decided to throw open the universe—perhaps instigated by reception of fan-fiction on 1632 Tech Manual—and invited other authors to help shape the series milieu and fictional canon and began putting together the anthology Ring of Fire.