Adventure of the Red Circle

Sherlock Holmes is approached by Mrs. Hudson to assist a friend of hers. The lady also lets furnished rooms and is now worried about what one of her boarders may be up to. The man had come to her 10 days before and paid her an exorbitant amount to ensure complete privacy during his stay. His meals are left outside his door and no one enters the room. Now the landlady can''t sleep at night wonderin...