[1] The novel depicts a fictitious German invasion of the United States in 1901, shortly after William McKinley begins his second term as US President.

[2] The plot is based on an actual diplomatic crisis that nearly brought the United States and the German Empire into war during the early 20th century.

However, the US Army is small, and its only large forces are occupying the newly won possessions of the Philippines and Cuba.

Meanwhile, in Connecticut, an American brigade, led by Funston, ambushes a German patrol and inflicts heavy casualties.

General Nelson Miles attacks the German positions along the Housatonic, in the fashion of the American Civil War, but is defeated.

At sea, the US Navy launches surprise attacks against German convoys in the English Channel and, closer to the American coast, sinks empty transports returning to Germany.

The German high command sends a massive convoy across the Atlantic Ocean, with both reinforcements and supplies, in the hope of trapping the American fleet.