In the waning days of World War II—just as the Allies liberate Paris—the Americans discover a frail, weathered letter in France’s Archives diplomatiques. Penned in 1865, it’s a confession by Jean-Pierre Barras, a French Creole from New Orleans. He claims that Abraham Lincoln was murdered in 1862 by the Sûreté—the French intelligence bureau—and that he, a Southern sympathizer and Lincoln look-alike, has impersonated the president ever since. Is the letter genuine? What could it mean for two allies still fighting the unconquered evil of the Third Reich?