Dr. Watson recounts an adventure that started on 20 March 1888. While the currently married Watson is paying Holmes a visit, a masked visitor arrives, introducing himself as Count Von Kramm, an agent for a wealthy client. Holmes quickly deduces that the visitor is in fact Wilhelm Gottsreich Sigismond von Ormstein, Grand Duke of Cassel-Felstein and the hereditary King of Bohemia. Realizing Holmes has seen through his guise, the King admits this and tears off his mask.
It transpires that the King is to become engaged to Clotilde Lothman von Saxe-Meiningen, a young Scandinavian princess. However, five years before the events of the story he had enjoyed a liaison with a "well-known adventuress", the American opera singer Irene Adler, whilst she was prima donna of the Imperial Opera of Warsaw. She has since retired and now lives in London. Fearful that should the strictly principled family of his fiancée learn of this impropriety, the marriage would be called off, he had sought to regain letters and a photograph of Adler and himself together, which he had sent to her during their relationship as a token. The King's agents have tried to recover the photograph through sometimes forceful means, burglary, stealing her luggage, and waylaying her. An offer to pay for the photograph and letters was also refused. With Adler threatening to send them to his future in-laws, which the King presumes is intended to prevent him from marrying any other woman, he makes the incognito visit to Holmes to request his help in locating and obtaining the photograph.
The photograph is described to Holmes as a cabinet (5½ by 4 inches) and therefore too bulky for a lady to carry upon her person. As regards expenses, the King says Holmes has carte blanche and gives him £1,000, exclaiming "I would give one of the provinces of my kingdom to have that photograph!" Holmes asks Dr. Watson to join him at 221B Baker Street at 3 o'clock the following afternoon.
en.wikipedia.org/wiki/A_Scandal_in_Bohemia
