
Fragments of encrypted intelligence reveal hidden criminal networks
Sherlock Holmes receives a numeric cipher from an informant tied to Professor Moriarty. Before the full key arrives, a frantic follow-up note warns that the informant was nearly discovered. Holmes uses pure deduction and an almanac to decipher the message, identifying a threat to John Douglas of Birlstone Manor. The encounter demonstrates how grand criminal schemes operate through insulated layers of intermediaries.
PART I The Tragedy of Birlstone → Chapter I The Warning

