We arrived at Piotr Flan’s pawnshop at one in the morning. Thanks to Macready’s cocaine, I felt nothing of my wound, but I knew this long walk would do me no good. Of course, the shop was closed and dark, but Holmes rang the bell repeatedly.

‘Holmes, we will have to wait until morning!’ I said, but he persisted.

‘Chances are he lives upstairs,’ said Holmes. ‘If not …’

Polly eyed the large padlock on the grating that had been placed in front of the door and front window of the shop. She removed a lockpick from her sleeve. ‘I could maybe unlock this,’ she said.

Holmes and I turned to her in surprise. I wondered briefly if everyone but me had mastered this skill. But before she could begin, a small light appeared in the back of the shop. A grizzled old man approached, peering at us owl-like from the interior, directing his lantern to shine on our faces. He had a strange corona of corkscrew hair that stuck out in all directions from an ill-fitting nightcap and an expression of what I imagined was permanent distrust on his lined visage.

He did not look inclined to open up. Polly put her lockpick away.

‘Vat you vant?’ he shouted, barely audible through the closed and locked door.

From his waistcoat, Holmes unclipped his gold watch, a high-quality timepiece which I had long admired, and held it up with what appeared to be a desperate and conciliatory smile.

Soon we faced Piotr Flan across a glass and mahogany counter filled with jewelled and gilded items. He had lit several lights and the small shop was now almost bright as daylight. His wife, in her nightdress and dressing gown, had come down to join him, apparently with the explicit purpose of keeping a sharp watch on Polly and me during the transaction. I felt a little like a rabbit in hawk territory. The woman was more than ready to pounce, and she carried a battered policeman’s truncheon in stark contrast with her flowered nightclothes.

‘All right then, you had better make this vorth my vile,’ said the man, with an accent I could not identify.

Flan spread out a large velvet cloth and tapped it, inviting Holmes to lay out his treasure. Polly began to wander through the small shop and the pawnbroker’s wife followed close on her heels. ‘Touch nuffink,’ the woman growled in a distinctly Cockney accent, ‘if ye know what’s good for yer.’

‘Just looking,’ said Polly. ‘No trouble, ma’am.’

‘Nuffink, hear me?’ the woman repeated, slightly jiggling the stick at her side.

Holmes laid the watch out on the velvet cloth. The pawnbroker took out a loupe and leaned in to examine it.

‘Got it! Both of ’em!’ cried Polly from across the room.