narrator is discussing with the famous Parisian amateur detective C. Auguste Dupin some of his most celebrated cases when they are joined by the Prefect of the Police, a man known as G-. The Prefect has a case he would like to discuss with Dupin. A letter has been stolen from the boudoir of an unnamed woman by the unscrupulous Minister D-. It is said to contain compromising information. D- was in the room, saw the letter, and switched it for a letter of no importance. He has been blackmailing his victim.