The unnamed 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.