: Father and uncle of a young man die in accidents. Sherlock Holmes discovers that the killings were committed by members of the secret society of the Ku Klux Klan.

Sherlock Holmes seeks help from a young man, John Openshaw. John's father invented particularly durable tires for bicycles and quite a wealthy man retired to retire. His brother Elias emigrated to America, bought a plantation in Florida, fought on the southerners side during the Civil War, and then returned to England with decent capital, where he rented a small estate. He led a solitary lifestyle, was a tough and quick-tempered man, drank heavily. He settled John and made him the sovereign master of the house. John was forbidden only to enter the room in the attic, where old chests and knots were kept.

One day, an uncle who never received letters received a message from India. From the envelope on which it was written "K. K. K ”, dropped five dry grains of orange. Uncle turned gray with fear and said that this was the reckoning for his sins, and now death awaits him. Soon, uncle burned some papers and made a will, in which he left everything to his brother, John's father. He punished John: if he cannot live in peace, then let him give everything that he has to his worst enemy.After this incident, my uncle did not part with the revolver, he drank even more and was mortally afraid of some danger. One night he was found dead in a pond. There was no evidence of violence on the body, and the police considered it suicide. Knowing how uncle was afraid of death, John did not believe it. Seven weeks passed between receiving the letter and the death of my uncle.

The father of John became the owner of the estate. First of all, he examined the attic, but found only a box with three letters "K" and insignificant papers on the service of his uncle in the army. Soon, father also received an envelope with the letters "K" and five grains of orange. The letter required him to put uncles of paper on a sundial. The father refused to contact the police, saying that he lives in a civilized country and will not pay attention to such nonsense. A day later he went to visit a friend. John was even glad that his father was far from home, safe, but his father fell into one of the chalk quarries in the area and crashed. The police concluded that it was an accident. John did not believe this and considered that his father’s death was connected with his uncle’s past.

Two years passed, and now John himself received the same letter from London. Since the police believe that these letters are someone’s joke, John turns to the great detective for help. He shows an old faded leaf that his uncle did not burn. It contains the names of several people who received grains of orange and died. This is the only paper that can interest unknown killers. Holmes advises putting it on a sundial and attaching a note to it stating that the rest of the papers have been burned.

The great detective ponders the situation.It is clear that Uncle John Openshaw had good reasons to leave America, as he led a secluded lifestyle and was constantly afraid of something. Studying the letters, Holmes concludes that they are all sent from ocean ports. And if you take into account the time between receipt of the letter and death, then, most likely, the writer was on a sailing ship. And this is not one, but several people. - This is the Ku Klux Klan Society. Most likely, the uncle who fought on the side of the southerners belonged to this society, and now they are hunting for the papers that he burned.

The next day, a note appears in the newspaper about the death of John Openshaw. From old magazines, Holmes finds out which ships were leaving from Pondicherry to London. His attention is drawn to a sailing ship called the Lonely Star: it is the second name of the state of Texas, and the ship is now in London. His captain and two sailors are Americans. Having put five grains of orange in the envelope, the great detective sends a letter to his captain with the inscription "Sh. H. for D. O. ”, counting on even a sleepless night for the addressee, and is going to inform the police.

The plans of the great detective were not destined to come true: in the Atlantic, the ship crashed.