A young girl, no older than ten, let herself into our sitting room. Her raggedy pants and jacket were too small for her growing frame, and her freckled face was smudged with soot and dirt.

"Mr. 'Olmes," she said. "I found the pipe shop like you asked! It's a tiny place out in Fulham with a funny name, The Red Ajagar."

"Brilliant work, Phoebe," said Holmes. Phoebe Brook was a member of Holmes's irregular intelligence network, and one of many agents that had been scouring the city on Holmes's orders since yesterday afternoon. Holmes tossed her a coin, which she caught in both hands with a clap. "I'm familiar with that part of town. Watson, will you join me? We must gather as much data on Flint as possible."

Holmes and I stepped out into the shifting, dense fog, and rattled by hansom cab through London to The Red Ajagar. The narrow shop was nigh invisible between a broad antique shop and a bookstore with a freshly painted storefront. There was a weathered sign over the door that displayed the name along with an illustration of a serpent and a series of Hindi symbols. Holmes and I strode into the shop, finding ourselves crammed between tight shelves of pipes, papers and other assortments of smoking paraphernalia. I squeezed past a woman that was studying a yellowed book on one of the shelves on my way to the counter.

"Namaste," said Holmes to the man behind the counter. "We're looking for a young man named Sam Flint. Black hair, six feet and two inches tall, muscular build. I believe he frequents this shop, and on Sunday he purchased a blend of opium and cannabis, as well as this pipe." Holmes pulled Flint's wooden pipe from his jacket pocket.

The man scratched his dark, curly hair with a wiry hand. He spoke with a thick accent. "Not sure. I see a lot of faces. I have trouble remembering."

"Would this help your memory?" said Holmes. He set a pound sterling on the counter and slid it across to the shopkeep. The woman by the shelf perked up and glanced at Holmes.

"Hmm, haan, it's coming back," the shopkeep said. "He was here on Sunday, like you said."

"What time?" said Holmes.

The shopkeep rubbed his chin. "Midday. 12:30."

"You've seen him here before?" said Holmes.

The shopkeep nodded. "Haan, a few times."

"And has he come here since?" said Holmes.

"No," said the shopkeep.

"We're trying to locate him, are you aware of anywhere else that he habitually frequents?" said Holmes. "Does he have any friends that you know of?"

The shopkeep shook his head. "Nishchit nahin, not sure. I did not know him well."

"Dhanyavaad, thank you for your help," said Holmes. He placed another coin on the counter along with a note with our contact information. Holmes asked that the man reach out to us if Flint reappeared, and then turned quickly and strode from the shop.

I followed him outside. "Well, that wasn't as illuminating as I had hoped," I said.

"Did you see the woman that left the store just a moment ago?" said Holmes.

"I saw her when we entered, yes," I said. "Almost crashed into her in the aisle."

"Did you see how she reacted to my remark about Flint?" said Holmes. "I watched her in the reflection of the glass case on the wall. She looked intrigued, and frightened, and she departed quite hastily."

"Which way did she go?" I said.

Holmes led me to the right through a billow of fog. I could scarcely see ten feet in front of me at times, and I had no sight of the woman from the shop. Holmes guided me through the streets at a walking pace, occasionally pausing and looking around. The streets were growing more populated by the minute, and I found that navigating in the fog was particularly troublesome. For five minutes we walked before I spoke in a hushed tone. "Holmes, can you see her in the fog? I've lost her."

"No, but I can hear her," said Holmes. "Based on the size, shape and material of her shoe, her weight, and the type of cobblestones that we're treading on, I had a fair approximation of the sound of her footfall. I picked out her steps among the sounds of the neighborhood, and we've been following her since. I thought we lost her back on Portlock Street, but the lingering aroma of her peach-scented hair product drew us back on track."

We continued in this fashion for another fifteen minutes. The fog began to partially clear, and I spotted our quarry again at last, turning left ahead of us into a one-story house on Wayworth Lane. She let herself inside and latched the door behind her. Holmes and I blended into a crowd that had formed around a street vendor's stall across the lane, then crept through the shadows of the alley adjacent to the house under the cover of fog. I heard the muffled voices of a man and woman conversing inside. Holmes stopped underneath a closed window, close to the source of the voices, and we eavesdropped in crouched silence.

"Did you get the blend?" said the man. "I can't go back to my old place to get my stash."

"There were men at the store, like policemen, but they didn't look like policemen," said the woman.

"What the hell are you talking about, Annie?" said the man.

"They were looking for you!" said the woman. "They talked about you with Bhagat, the shopkeep. Sam, what's going on? The police are offering a reward for information on you, I saw it in the paper!"

"You said you wouldn't ask questions," said the man.

Sam. I looked over at Holmes; he had heard it too. We seemed to have crossed paths with Sam Flint's confidant at The Red Ajagar, restocking his lost narcotics, and we had the good fortune of following her undetected back to Flint.

"I need to know what you've gotten yourself into!" said the woman. "Are we in danger?!"

There was a thump and a muffled cry. I could hear the woman whimpering in pain and surprise. My knuckles whitened as we snooped on their domestic dispute, I was tempted to climb through the window and break up their quarrel. Holmes raised a hand to pacify me.

"Everything is going to be fine," said the man. "I just need to lay low here for a few more days, and this will all blow over."

Someone knocked on the front door, four quick raps, and a familiar voice called out. "Ms. Annette Pandy? Are you home?"