The yellow fog was finally beginning to shred under the influence of a keen northern breeze as we emerged from the subterranean mouth of the Charing Cross vaults. The gas lamps along the Strand were flickering out, their pale amber light replaced by the cold, steel-grey dawn of a London morning. The city was waking up, entirely oblivious to the fact that the very ground beneath its busiest thoroughfare had been preserved by a fraction of a millimeter.
Holmes walked with a brisk, swinging stride, his long hands buried deep within the pockets of his dark traveling cloak. The exhaustion that usually followed his intense mental exertions was entirely absent; his features were set into a hard, vigilant mask that told me the resolution of the infernal machine was merely the prelude to a much grander conflict.
"He has broken cover, Watson," Holmes remarked as we hailed a passing hansom cab through the melting frost. "For years, Professor Moriarty has been a mathematical abstraction to us—a shadow behind the burglaries, a silent partner in the international fences, a whisper in the ears of foreign spies. But tonight, he was forced to step onto the damp ballast of the underground line. He has committed his own hands to the mechanism."
"And he escaped through the ventilation shafts," I said, leaning back against the leather cushions of the cab as it rattled toward Baker Street. "He could be anywhere in the metropolis by now."
"He will not remain in the metropolis," Holmes replied, staring out at the frost-rimed windows of the shops. "Moriarty is a master of logistics. The moment the morning papers fail to report the destruction of the Charing Cross junction, he will realize his equation has been solved. His network of continental agents is already shattered; he has nowhere to turn but his final, most secure redoubt."
When we returned to our old sitting-room at 221B, the warmth of Mrs. Hudson’s fire was a welcome contrast to the foul chill of the railway tunnels. Resting upon the mahogany table, beside a fresh pot of coffee, was a single, sealed envelope of heavy blue paper. It bore no postmark, but the address was written in that same precise, academic hand that we had seen on the black cardboard square.
Holmes ripped it open with a swift movement of his thumb. Inside was a single sheet of paper containing a list of seven European cities, each associated with a specific date and a column of figures. At the very bottom of the page, written in bold, clean strokes, was a final deduction:
The ledger is balanced in London, Mr. Holmes. Let us see how it stands in the mountains.
"A map of his continental assets?" I asked, looking over his shoulder.
"No, Watson," Holmes said, his eyes gleaming with the terrifying light of a man who has found his ultimate purpose. "It is his itinerary. He is drawing me out of England, away from the protection of Scotland Yard, into the isolated passes of the Swiss Alps. He knows that as long as we both breathe the same air, the world is not large enough for our respective philosophies."
He stepped over to his corner desk, lifted his heavy leather traveling bag, and set it firmly upon the table. "The winter is over, Watson, and the shadow of the Blue Carbuncle has finally been traced to its source. But a far greater ledger opens today. Pack your service revolver, see to your domestic arrangements with your excellent wife, and meet me at Victoria Station for the morning boat-train. The final hunt has begun."
