The Adventure of the Seven Clocks
Holmes is consulted by a young lady, a companion to an older woman, about the eccentric behavior of a young man she has met. He behaves normally, but becomes a raging maniac whenever he encounters a clock. The young woman personally has seen him smash two clocks and heard from the man's servant of five other incidents. Holmes must travel to a distant seaport to gather information to resolve a horrible, terrorist scheme and solve the mystery of the aberrant behavior.
"But not only does Charles smash clocks," she went on. "He buries them in the snow, and even hides them in the cupboard of his own room."
Sherlock Holmes had been leaning back in his chair with his eyes closed, and his head sunk into a cushion, but now he half opened his lids.
"In the cupboard?" exclaimed he, frowning. "This is even more singular! How did you become aware of the circumstance?"
- The Exploits of Sherlock Holmes, Chapter 1