In the winter of 1944, an American brigadier general was held at gunpoint by his own soldiers for saying the Chicago Cubs were in the American League. This episode explains how that happened by tracing Operation Greif, the Nazi plan to send Germans disguised as Americans behind Allied lines during the Battle of the Bulge, and the man chosen to lead it, Otto Skorzeny, the six-foot-four commando with a dueling scar who had rescued Mussolini by glider and kidnapped the son of Hungary’s regent.

We follow the plan from Hitler’s October 1944 briefing at the Wolf’s Lair through the legal anxiety over the Hague Convention, the logistical fiasco of two broken Sherman tanks and Panthers dressed in sheet metal to mimic M10 tank destroyers, and the discovery that only 10 of 2,500 men spoke convincing American English. The elite Einheit Stielau commandos reversed road signs, cut wires, and spread a rumor that Skorzeny was coming for Eisenhower, which locked the Supreme Allied Commander in his Paris headquarters over Christmas. The episode closes with the firing-squad executions of captured commandos and the 1947 Dachau trial in which Skorzeny was acquitted after a British agent testified that the Allies did the same thing.

• Pink scarves, yellow triangles, and guns at nine o’clock: the fragile friendly-fire safeguards
• How correcting a typo on forged ID cards gave the fakes away
• Why trivia about state capitals and Mickey Mouse replaced passwords at checkpoints
• The friendly-fire tragedies caused by paranoia in the Ardennes
• Ruse of war versus perfidy: the legal line that saved Skorzeny’s life