One night in March 1888, I walked past my old home at 221B Baker Street. I was married now and lived in another house, but I saw my old friend Sherlock Holmes at the window, so I rang the bell. Holmes was happy to see me. He looked at me for a moment and said, “You have put on seven and a half pounds, Watson, and you have been out in the rain.” He was right, of course.

“How do you know?” I asked. “I see it,” he answered. “There are small cuts on your left shoe. Someone cleaned the mud off it carelessly. You see, but you do not observe.” Then he gave me a letter. It said that a visitor would come at a quarter to eight that night, and that he wanted to talk about a very important matter.

At exactly a quarter to eight, a tall man came in. He wore rich clothes and a black mask over his eyes. “I am Count Von Kramm,” he said. Holmes smiled. “I think,” he said quietly, “that I am speaking to His Majesty, the King of Bohemia.” The man was surprised. Then he took off his mask and threw it on the floor. “You are right,” he said. “Why should I hide it?”

The King explained his problem. Five years ago, he met a beautiful opera singer called Irene Adler. They were close friends, and they had their photograph taken together. Now the King was going to marry a princess from Scandinavia. If the princess’s family saw the photograph, there would be no wedding. Irene Adler had the photograph, and she did not want to give it back.

“We have tried to steal it five times,” said the King. “We searched her house and her luggage, but we found nothing.” Holmes laughed. “It is quite a pretty little problem,” he said. The King gave him a thousand pounds for his expenses, and Holmes promised to find the photograph.