The Adventure of the Engineer's Thumb

 In The Five Orange Pips, a young Sussex gentleman named John Openshaw tells the strange story of his uncle Elias Openshaw, who came back to England after living in the United States as a planter in Florida and serving as a colonel in the Confederate Army. His uncle begins receiving threatening letters inscribed “KKK” and including five orange pips. He is killed shortly thereafter. The job of unraveling this sordid transatlantic mystery falls to Holmes and his trusty companion, Dr. Watson. 

In "The Boscombe Valley Mystery", Inspector Lestrade summons Sherlock Holmes to a community in Herefordshire, where a local landowner has been murdered outdoors. The deceased's estranged son is strongly implicated. Holmes, employing his trusty magnifying glass quickly determines that a mysterious third man may be responsible for the crime, unraveling a thread involving a secret criminal past, thwarted love, and blackmail.

 Dr. Watson is called upon late at night by a female friend of his wife whose husband has been absent for several days. Frantic with worry, she seeks help in fetching him home from an opium den. Watson finds his friend Sherlock Holmes in the den, disguised as an old man, trying to extract information about a new case from the addicts therein. 

Dr. Watson recounts that a masked visitor to Baker Street is quickly deduced to be the hereditary King of Bohemia. The King is to become engaged to a young Scandinavian princess. However, five years before, he had a liaison with American opera singer, Irene Adler. Fearful that the marriage would be called off, he had sought to regain letters and a photograph of Adler and himself together. The ensuing adventure involves disguise, subterfuge and Holmes' legendary powers of deduction.

In "A Case of Identity", Miss Mary Sutherland, a woman with a substantial income, is engaged to a quiet Londoner who has recently disappeared. Of the fiancé, Mr. Hosmer Angel, Miss Sutherland only knows that he works in an office in Leadenhall Street. All his letters to her are typewritten, even the signature, and he insists that she write back to him through the local Post Office. The climax of the sad liaison comes when Mr. Angel abandons Miss Sutherland at the altar on their wedding day. Holmes reaches a conclusion quite quickly and advises his client to forget Mr. Angel.