‘No pseudonym. Is my real name,’ said the locksmith.

‘Holmes, you speak Norwegian?’ I asked.

Holmes frowned at me and nodded curtly. ‘As you wish, Mr Lossop. I am sure there is an interesting reason for your choice to remain anonymous. Though one might easily trace you by your speciality. In any case, we bring before you a unique challenge. I am Sherlock Holmes. Ah, I see that you have heard my name before. This is my friend and colleague, Dr Watson. He received a package in the mail, containing a highly decorative silver box with an unusual lock. Both the good doctor and I have attempted to open this box—’

Lossop held out his hand, palm up, to receive the object. I noted thin, spidery fingers and long nails.

‘Give,’ he said.

‘But let me complete the thought. Watson here brought it to – who was it, Watson?’

‘Boobbyer on the Strand, and Chubb’s.’

The locksmith snorted in derision.

‘—with no luck. I have done my research. Your name, hard to come by, Mr Lossop, was at last given to me. You are in a class by yourself, apparently.’ Holmes smiled solicitously.

‘The box, please. I shall have a look.’

I took the scented soap container from my satchel, extracted the mysterious and beautiful silver box, and placed it on the counter between us.

Lossop crossed his arms in front of him and leaned towards it. He stared at the box for a full minute without touching it. Thoughts flickered across his sharp features, and a slow smile lit his pale face.

Holmes and I waited patiently. The locksmith then picked up the box, placed a jeweller’s loupe over his spectacles and examined it minutely. He hummed tunelessly, and brought a candelabrum closer, holding the box to the flickering light to scrutinize something that evidently interested him.

He put the box down with a smile.

‘Well, can you open it?’ I asked.

‘It is most probable. But not quickly.’

‘If you cannot, can you break it open?’

‘Yes, but that may well destroy the contents.’

This confirmed my fear.

He held up the box and pointed to a place on the side. I saw nothing but the swirling Celtic tracery. ‘Look closer,’ he commanded, and handed me the loupe.

I did, but could see nothing. The fine workings on the box were complicated, with lines of different depths, small pinpoint dots, and—

Holmes took the box and the loupe from my hand and, holding it up to the light, examined the area the locksmith had indicated. He handed both back to Lossop. ‘I see,’ he said.

‘Well, I don’t,’ I said with some irritation.

‘Someone tried to drill into this box, revealing that it is lined with something. I presume this material is much harder than silver, and blocked the drilling,’ said Holmes.

‘Exactly,’ said Lossop.

‘Like what?’ I asked.

‘A steel alloy, perhaps, even with tungsten?’

‘Ha!’ cried Lossop. ‘Tool steel! Nothing harder. Except diamond.’