Here's the jacket blurb:
It is the year 1636. The United States of Europe, the new nation formed by an alliance between the Swedish king Gustavus Adolphus and the West Virginians hurled back in time by a cosmic accident, is on the verge of civil war. His brain injured in the war with Poland, the USE's emperor Gustavus Adolphus is no longer in command. Enter Swedish chancellor Oxenstierna, a leader of aristocratic reaction against democracy. His goal: to assemble the forces of the hidebound ruling class in Berlin and drown the revolution in a bloodbath.
In Magdeburg, the capital of the USE, Mike Stearns' wife Rebecca Abrabanel is organizing popular resistance to Oxenstierna's plot. As part of the resistance, the American musician Marla Linder and her company of down-time musical partners are staging an opera that will celebrate the struggle against oppression. Princess Kristina, the heir to the USE's throne, is now residing in Magdeburg and is giving them her support and encouragement.
But another plot is underway–this one right in the heart of the capital itself, and with murder as its method. The only people standing in the way are a crippled boy and the boxing champion who befriended him, and an unlikely pair of policemen. Can the American detective Byron Chieske and his down-timer partner Gotthilf Hoch thwart the killers before they succeed in their goal?