Holmes’s eyes narrowed dreamily. “It had crossed my mind. Middleton here’s a ruddy connoisseur of the stuff. We’ve been rambling about all night. Stumbled onto that fellow Blackstone, what was in Egypt a few years back.”

“Johnny Blackstone? Haven’t run into him for over a week now. Your friend here may keep mum more than is usual, but it’s a sight more peaceful than that Blackstone’s balmy talk.”

“That’ll be the black drop. He means no harm.”

“I daresay you’re right. But he was in a dark mood last I laid eyes on him.”

“I meant to stop by his digs last week—he allowed as he’d be the better for company, but damned if there weren’t a pipe in my hand when I said it. It was as much as I could do to recall it were in Spitalfields, let alone the address.”

“He lives in Sandy’s Row, over Widegate Street area. Keeps himself to himself for the most part, but I dropped in for a nightcap, last month it must have been, though I’ve not been back since. There he is up at the back of the building, windows all stopped up with scraps. Small wonder he’s so few folk looking in.”

“Maybe he likes it that way. At any rate, I’ve Middleton to share a morning pipe if Blackstone’s too deep in the dumps to crawl out of ’em.” My friend shrugged, finishing the last of his beer.

“You don’t mean to stop by now, do you?” Kettle asked. “Lord knows what den he’s holed up in. He’s that cracked—sets off at one or two in the morning on his rambles and never thinks of his rooms till late the next day. If you want to find him there, look in tonight before midnight.”

We said our good-byes and ambled outdoors. I could see the bustling eastern side of Spitalfields Market across the road from us, and the smell of livestock and freshly unearthed onions wafted along the street. My friend was a taut whipcord of suppressed vitality as we set off aimlessly down the road.

“That’s done it,” Holmes said quietly, but with the thrill of the chase in his clipped tenor. “I had the house number yesterday from a fellow called Wicks over three cups of gin.”

“Have you all this while been seeking out Blackstone’s lodgings?”

“Indeed yes. It is no joke to infiltrate a network of people and, through expert maneuvering, convey the impression that you have existed on the periphery for far longer than anyone can recall.”

“I was astonished at their manner toward you. You might have known them for years.”

“For the first five days, I divided no less than eighteen hours a day amongst the most popular dens between Whitechapel and Limehouse, my brain nothing more than a massive sponge. I flatter myself I had the lay of the land fairly quickly, deducing as much as I observed. Patterns began to emerge. When I felt confident enough, and these fellows had grown used to the sight of me, I began dropping names—a brother who’d reenlisted, a friend who’d died, a girl who hadn’t been seen in years. I established undisputed, unprovable connections. At last my own story came out. Where had I been? At sea, these four years. Soon I was so universally trusted that I could elicit information with very little fear of being caught.

“When Mr. Li conveyed the message that Blackstone was at the Three Cobras, I arrived mere minutes too late, but his departure easily occasioned talk of him amongst his associates. Slowly, as if I were piecing together a smashed Abyssinian urn, an image emerged. He has not lived long in the area, and no one knew him before August. He resides alone, more often than not going about in a uniform in spite of his discharge. He is a mass of contradictions: despite his rugged good looks and cynical charm, he shuns the company of women. Though his mood is nearly always black and his temper violent, he is well liked by the other lads for his clever speech and free purse.

“I desired nothing more than to find out his lodgings, but it soon became clear that the slippery devil hardly ever receives guests. It could not have been more taxing, Watson—it was a more delicate combination of deductive reasoning and guarded conversation than I ever anticipated, but the final link you witnessed yourself, and the end of the search lies before us. I confess that I feared when you arrived, your presence would disrupt my little fiction. Thankfully, I had nearly reached my goal, and a trusty comrade will now be of inestimable use.”

“No one else could have accomplished so much, and without arousing the slightest suspicion,” I declared warmly.

Holmes waved away my compliment, but the gesture was a gentle one. “Your envelope is cause for the greatest concern. It was postmarked Saturday, the twentieth of October. Tavistock has had more damning information in his hands for over two weeks now. At any moment, he may publish another stylishly phrased defamation. Then there is the Ripper himself to consider; since he set out to terrorize the unfortunates of Whitechapel, he has never paused this long in his ungodly work. If the pattern of dates continues, he will strike again no later than the eighth of November.”

“May we run the villain down tonight, for their sakes.”

“For all of London, my dear fellow,” he replied grimly. “But above all, for their sakes.”

We passed the day easily in the ramshackle room, Holmes chatting desultorily of violins and their origins in sixteenth-century Italy until the sun had fallen. After a bowl of stew and tumbler of whiskey in a nearby tavern, we set off under the clearest night sky we had seen in some time. My friend steered us immediately north, and I quickly recognized our path as we passed the railway depot and crossed Aldgate High Street. A group of street urchins were setting off a riot of firecrackers in an old cistern, and I recalled as a shower of golden sparks fell upon the roofs of the warehouses that it was Guy Fawkes Day, the fifth of November.

“I cannot express how galling it was to have the house number from a semidelirious sot moments before he lost any pretense at consciousness,” Holmes remarked as the crack and hiss of gunpowder faded into the distance. “However, despite the delay, it was as well we learned of the street from Kettle, for he knows more of Blackstone’s habits than anyone.”

“What do you imagine will happen, Holmes?”

“Suffice it to say we had best prepare for anything. In any event, I don’t suppose either of us will ever again fail to remember the fifth of November.”

We strode down a slick side street littered with whimsical configurations of rubbish gathered into heaps, which I gradually perceived were actually for sale. Broken pipes, cracked cookware, split boots, rusted keys, and twisted cutlery spilled onto the cobbles, and all the smells of the thrice-mended clothing permeated the air. Through this purgatory of lost objects Holmes picked his way easily, until we emerged onto an open byway, edged with warehouses whose smokestacks churned black exhalations into the night. Here numerous bonfires blazed, with crude Guy Fawkes effigies roasting above them, and the locals turned spitted potatoes over the coals as they cheered the roar of distant detonations.

My friend stopped at a corner and pointed without hesitation to a rickety structure which leaned against its neighbour for succour in its extreme old age. Though the street was unmarked at that juncture, I had no doubt but that Holmes’s encyclopedic knowledge had led us directly to Blackstone’s dwelling place.

“You have your weapon about you, I trust?”

“My service revolver is in my pocket.”

“Very good.” He plunged off the pavement, such as it was, and we approached the sagging grey door. The detective’s knock produced nothing more than a hollow thumping which died away the instant it was produced.

“There seems to be no one on the ground floor,” he whispered, cracking the lens of his dark lantern. “Let us see if there is any sign of life on the upper levels.”