Martha had not been wearing a mask. Martha was the mask.

‘There, now. Sleep now.’

Sarah lay helpless, the light of a single candle casting twisted shadows upon the wall. She would have been paralysed with fear, had she not been too weak to move anyway.

Mary was coiled about her bodily, but Sarah had been in her clutches for longer than that. She had drunk from glasses Mary had given her, taking them gratefully in her thirst. The pages of Christison flashed in her memory, another fragment: a fierce thirst was symptomatic of atropine. She had been poisoned.

The candle flickered and the shadows danced as a wind blew through the house, a summoned spirit rushing closer. Death was coming for her. She could sense it. She could hear it.

The witnesses to Mary’s other crimes had said the dying were assailed by phantoms, and there was one here now: a demon. A monster.

The last thing she saw was the creature’s horrifying visage before blackness came upon her.

SEVENTY-SEVEN

aven leapt from the curricle even before it had stopped, his feet splashing through the puddles on the wet flagstones in the rain-lashed darkness. McLevy was scrambling at his back as he barged inside and tore through the house. It was strangely cold within, the chill air in the hallway indicative that there was a door open elsewhere.

They both stopped at the entrance to Sarah’s bedroom, aghast at the scene which confronted them. The room was illuminated by a solitary candle, but it cast light enough to reveal that they were not the night’s first visitors.

‘God almighty,’ McLevy said. ‘Who did this to her?’

Raven turned on the gaslight and Sarah roused in the bed, responding to the intrusion. Before them Mary Dempster lay trussed on the floor, her hands and ankles bound behind her and tied together like she was an animal ready for the spit.

Her hair was black, as Raven remembered it, and a blonde wig was stuffed into her mouth. He recalled her grabbing at her head in the high wind, he had assumed to secure her hat. It had been to avoid revealing the true colour of her hair. He observed that the wig had been fixed in place by a length of ribbon, tied tightly around her head so that she couldn’t shout for help. Raven approved. A neighbour or passing stranger responding to her cries might have freed her, providing her with the chance to escape.

‘Raven,’ said Sarah urgently, trying to sit up. ‘She is … Martha is—’

‘I know,’ he told her, hurrying to her side.

McLevy knelt down next to Mary and pulled the gag from her mouth.

‘Oh, thank heavens you came,’ she said. ‘I was attacked by a madman. My name is Martha Dempster. I am a nurse, working here for Dr Raven.’