‘I dare say,’ he agrees, with no emotion. ‘But you were spared, and you argued your legal case with the sheriffs successfully, just as I suspected you would be able to do. Now, I have news for you. My Mrs Rose is doing well for herself. So well, in fact, that she has taken rooms a ten-minute walk south-west of here, near Greyfriars. I have the address, for I have followed her, but she doesn’t know this, and I think she needs a delicate touch. I can’t simply turn up unannounced or approach her in the street.’

‘And that is where I come in,’ I said warily.

‘You most beautifully do.’ He coughed and wiped his mouth with a pristine kerchief. ‘I desire her, Mistress Dickson, like I have wanted nothing else in my life. I crave her artful ways of the bed.’ He leaps to his feet. ‘Come, he insists, ‘I have even prepared her a chamber.’

I follow him towards a small room off the parlour, my fear making me feel quite sick. The Turkish carpet beneath my feet is thick and soft. Enough to muffle a girl’s cries. The door swings open. The room beyond is appointed as one might decorate a room for a princess. The four-poster bed is of walnut, with carvings. A heavy-looking bedspread is folded across it, tightly and expertly. There are gold tassels everywhere too: dangling from the curtains and the bed canopy. A dressing gown hangs from a coat-stand, decorated with snarling brown snakes with red tongues, and I nearly jump out of my skin when I see that.

‘That, I bought from a trader who’d had it shipped from the Orient,’ Dr McTavish states, with pride. ‘Do you like it?’

‘I do not,’ I say. I cannot take my eyes off the snake-gown, for it is exactly as I see the snake in my dreams, swirling and coiling. I put my hand on the door to steady myself.

‘Well, it is not for you anyway,’ he replies. ‘It’s for Mrs Rose. She will be my special guest. She will soon realize that she will want for nothing.’

I drag my eyes from the snake-gown and look around me again. This room would be a chamber of delights, were it not for two things. First, he has had the window secured, which means there is no natural light at all, only the light from the lamps. By ‘secured’, I mean boarded, and the boards look to be nailed into the wall. And over them are iron bars that remind me so much of the Tolbooth Jail that I can’t look at them for too long. Second, he has fastened to the wall, by the bed, a pair of iron chains.

‘Do you mean to keep Mrs Rose your prisoner?’ I gasp.