I screamed.

Cursing inwardly, I tried to keep my voice soft and soothing. Damn her! A few minutes more and the whole affair would have been concluded. I pulled the cloak over her face to try and limit the reviving effect of the cold, put my arm around her and whispered gently. But Effie was coming round quickly, her eyes moving fretfully beneath her closed lids, her breathing rapid and irregular. One-handed I opened the laudanum bottle, trying to coax her to take a few drops.

‘Come on, Effie…shh…just drink this…come on, that’s a good girl.’ But I could not persuade her to take the drug. Instead, disastrously, she began to talk.

Henry wasn’t far away; he had panicked when Effie opened her eyes and run a few steps down the path, but he was still within earshot. If Effie let slip a single word about our plan I knew that even now Henry was shrewd enough to guess at the rest. I put my arms tighter around her and tried to muffle her words.

‘Come on…’ I said, more urgently. ‘Drink this, and be quiet.’

Her eyes focused into mine. ‘Mose,’ she said quite clearly, ‘I had such a strange dream.’

‘Never mind that,’ I hissed desperately.

‘I…’ (Thank God, I thought, she was drifting again.)

‘Look, just drink your medicine, like a good girl, and sleep.’

‘You will…you’ll come back for me, won’t…won’t you?’

Damn her! Henry was coming back along the path. I tried to pinch her nostrils and force the laudanum down her throat, but she was still talking.

‘Just like…Juliet in the tomb…like Henry’s painting. You’ll come, won’t you?’

Her voice was suddenly very clear in the night.

You have to understand: I never intended her any harm. If only she had kept quiet for a few minutes more…it really wasn’t my fault. I didn’t have the choice! Henry was almost at my elbow: another word and the whole thing would have been ruined. All our effort for nothing. I couldn’t keep her quiet.

Understand that I acted purely on instinct: I never meant to hurt her, simply to keep her quiet for the few minutes I needed to get Henry out of the way. It was dark; my hands were numb from working with the stone, and yes, I was nervous, anyone would have been nervous.

All right, all right. I’m not proud of what I did, but you’d have done the same, believe me. I hit her head, not very hard, but harder than I intended, against the edge of the sepulchre. Just to keep her quiet. She wouldn’t have thanked me if because of me Henry had tumbled to our plan; she would have wanted me to do what I could, for her sake as well as for mine.

The bitch could have ruined everything.

She crumpled into the snow and, as I picked her up I saw a bead of blood darkening the hollow where her head had rested; just a single round patch the size of a penny. I fought back panic. What if I had killed her? She was frail, already close to collapse…it would not have taken much to finish Henry’s work. I brought my face close to hers and listened for her breathing…there was none. What did you expect me to do then? I couldn’t react: Henry would immediately have suspected. There was nothing I could do but wait. Ten minutes, and Henry would be gone. Then I could see to Effie. I couldn’t believe that little tap on the head had killed her: more likely I hadn’t heard her breathing because of the noise of the wind. I couldn’t afford to panic on account of something so trivial.

Gently I brushed the snow from her and carried her to the vault. Looking into the opening I could see that it was dark in there, and I hung Henry’s lantern above the entrance so that I wouldn’t fall. There were a dozen narrow stairs leading down, some broken and rotted with age. Carefully I carried Effie’s limp body down and looked around in the gloom for a place to put her. It was slightly warmer in the vault than outside, and it stank in there, of age and mould, but at least the coffins were out of the way, hidden behind stone slabs on their shelves and sealed with cement. I carried her to the back of the vault where there was still an empty shelf wide enough to lie on. I made a pillow for her head with my knapsack, wrapped the cloak tightly around her and left her there as I made my way back up the steps towards Henry.

I sealed the vault again, scattering earth and dead leaves over the slab so that my interference would not be noticed. Then I shut the door and wedged it with a stone. Turning to Henry, I handed him the lantern and smiled.

For a moment he stared at me, his eyes blank, then he nodded and took the lantern.

‘So…it’s done,’ he said softly. ‘It’s really done.’

Oddly enough, he sounded more lucid than he had been all night: his voice was clear and almost indifferent.

‘You will remember what to do next, won’t you?’ I urged, wary of Henry’s new serenity. ‘The presents. The tree. The housekeeper. Everything has to be perfectly normal.’ I was uncomfortably aware that if I had really killed Effie, we were risking my neck as well as his.

‘Of course.’ His tone was almost arrogant. He half turned away, and I was struck by the peculiar thought that I was being dismissed. At that thought I grinned, and suddenly I found myself laughing, choking with sour hilarity among the graves, the sound absurdly appropriate to that Gothic night as the heavy snowflakes filled my mouth, my eyes, my hair. And Henry Chester began to move slowly down the path, the lantern held high, like some stern Apostle leading the dead along the road to hell.

For a time beyond time there was nothing. I was beyond motion; beyond thought, beyond dreams. Then the world began to return; single thoughts drifted through my mind like isolated notes of an unfinished symphony. I moved through clouds of memory in search of myself until suddenly a face floated in front of me like a balloon and I remembered a name…then another…and another, fluttering around me in the haze like a hand of spilled cards. Fanny…Henry…Mose…

But where was she, my dark sister? My fellow-dreamer, my twin, my closest friend? In rising panic I looked around for her and realized that, for the first time since we met and travelled together, I was alone; alone and in darkness. A wave of memory broke upon my head and I cried out in dismay: my voice echoed oddly against frozen stone and, in the aftermath of the black wave, I realized where I was. I tried to move, but my body was stone, my hands frozen clay. As I forced my rigid limbs into movement, I found that I could raise myself on to my elbows. Painfully I began to search the area immediately around me, my eyes dilated against the endless dark. I was lying on some kind of ledge-my numb hands could not tell me whether it was of wood or stone, but I could tell that it ended a few inches to the left of me. What was beyond it I could not guess, preferring to stay quite still where I was rather than risk touching the rotting boards of some ancient coffin…Above me I could faintly hear the sounds of the night and the high whine of the wind.

Thinking of the outside I was for a moment disorientated, imagining myself deep under the ground with the roots of the cedars all around me. Tomorrow there would be people walking down the snowy path to church; children in bright coats and hats dreaming of sledging down Highgate Hill; lovers arm-in-arm, blinded by the sun on the snow; carol-singers with lanterns and hymn-books…and all the time I would be there beneath them, frozen into the dark stone with the dead around me…

At the thought I started and cried out involuntarily: No! Mose would come. I was supposed to wait, and he would come to find me. The realization flooded me with a great relief. For a moment I had been so confused that I had believed I was already dead, imprisoned for ever beneath the snow and the marble.