Card 54 of 82
The Secret Room
Sherlock Holmes had a secret room whose key he kept in a dressing table. He allowed nobody inside, neither Dr. Watson nor Mrs. Hudson. But when Holmes and Watson went out, Mrs. Hudson decided to see what was in the room. She took the key, opened the door and went in. She walked around the room, went up to the table and opened the book lying on it. Suddenly she heard footsteps below and Holmes's voice: "I forgot something." Mrs. Hudson quickly closed the book, put it back in its place, went to the door, turned off the light, went out, locked the door and managed to put the key back in its place. Holmes took the key, opened the door, looked into the room and immediately asked: "Mrs. Hudson, why did you go into my room?" How did Holmes know that Mrs. Hudson had been in his room?