A beautiful American lecturer at the University of Wisconsin, Mildred Fish, married Arvid Harnack, a visiting Rockefeller Foundation fellow and returned with him to Germany in 1929. In 1942, she was tried as a member of the “Red Orchestra,” a Russian spy network in Germany. Her original trial ended in a recommendation of six years’ hard labor, but Hitler demanded a retrial which resulted in the death penalty. On February 25, 1943, the 40-year-old woman was executed by guillotine. Why was Hitler so implacably set against members of the Red Orchestra?

Because they had cost him the war. Here’s how:

On June 22, 1941, Hitler’s troops began a surprise invasion of Russia, Operation Barbarossa. They expected victory within three months. The Russian spy network in Europe,  “The Red Orchestra,” warned of the attack, but Stalin did not believe the warnings. As a result, the Russians had mammoth losses—over 1 million troops killed at first.

Stalin learned to trust The Red Orchestra, a spy network with cells in Brussels, Germany, France and Switzerland. His generals planned their strategy based on German battle plans, delivered to Moscow within 10 hours of their adoption!

The Russian armies regrouped and went on the offensive on December 5, 1941, with German troops only 50 miles from Moscow. Knowing the enemy’s plans, the Soviets could set a trap, and by July 20, 1942, the German troops were in full retreat.

The Germans didn’t win in three months according to their schedule. After 13 months  the fatally crippled German troops retreated in failure. The tide had turned against them–especially with the entry of the United States into the war after Pearl Harbor.

The Red Orchestra was finally wiped out after three years. But it was too late. The damage had already been done.

V.E. Tarrant’s book, The Red Orchestra, tells the story of the spy ring’s achievements and the Germans dogged hunting down of the men and women who helped to defeat their invasion of Russia so decisively.