They came together now, like ghostly twins, their faces merging one into the other so that for an instant Effie would stare at me through my daughter’s eyes, or Marta’s laughter filter through the veil of Effie’s smile. At last she was there, almost visible, and it seemed that my heart would burst for love of her, love of them both. She was happy now, happier than she had ever been before, knowing that she had come home, that she was safe with her mother again, safe with her sister. Since the night I asked her to name the Hermit I had not needed her memories: that part of her slept, sinking deeper into the murk of things best left forgotten, and she had stopped dreaming of the Bad Man and what he did to her long ago. In fact, with the help of my potions she remembered very little.

She was content to sleep in her room with her books and toys around her; she played with Meg and Alecto and, when Henry came, she played with him, too. Every visit dragged him deeper; we dosed him with chloral and strong aphrodisiacs, flayed him with kisses which left him gasping on the floor long after Marta had left the room. He lost his power to distinguish reality from fiction and I am certain that if I had shown him Effie in her undisguised form he would not have recognized her. Her body had grown thin and sores bloomed on her arms and chest; but Henry was beyond noticing them. My Marta shone through Effie’s flesh, transcending it, growing strong; and he was hers, all hers. I watched him become vague-eyed and listless as weeks passed, jumping at shadows, and my heart was filled with black rejoicing as we fed on him, my daughter and I. Don’t let anyone tell you vengeance isn’t sweet: it is. I know.

Mose came to see me twice. His creditors wouldn’t wait for ever, he told me, and he didn’t understand what we were waiting for. I lent him fifty pounds to tide him over and he seemed happy enough to play along for a while. Soon, I told him. Soon.

Just give my Marta time to grow.

Five more weeks passed and on five more Thursdays Henry Chester stumbled blindly up the steps of my house into a nightmarish rapture of lust. She walked right through him, my wraith, emptying him of all his assurance, his pretentious male superiority, his religious bigotry, his icons and his dreams. If he had not been Henry Chester I could have pitied him, but the thought of my sad little ghost and what she had once been cleared my head of all ambiguity. He had had no pity for my Marta.

Those five weeks saw the fleeting of a grey, lustreless autumn; winter came early and a hard, ringing black wind brought ice to the roads and tore the sky into dark, tattered streamers of grey. I remember Christmas decorations in the London shops, fir trees on Oxford Street and tinsel along the gaslamps, but at Crook Street the windows and doors stayed unadorned. We would celebrate later.

Henry came for the last time on 22 December: night fell at three that afternoon and by nine the thin rain had turned to sleet and then to snow, barely whitening the cobbles before turning black. Perhaps it was going to be a white Christmas after all. Effie came early, wrapped to the eyes in her thick cloak; I looked at the sky and almost turned her away, thinking that Henry would never come on such a bleak, dreadful night. But Marta’s faith was greater than mine.

‘He’ll come,’ she said with impish assurance, ‘especially tonight.’

Oh, my lovely Marta! Her smile was so beautiful that I was tempted to abandon my revenge. Wasn’t it enough to have her again, to hold her in my arms and feel her cool skin against my cheek? Why risk that for a sterile victory over a man already damned?

But of course I knew why.

For the moment she was still his. In his eyes half of her was still Effie, and she would never fully be mine until he abandoned his claim. While he continued to see them as separate individuals they could never be truly united, never return to the good, safe place they had left. They would be two floating halves, disintegrating slowly in a void of forgetfulness from which only a mother’s love could drag them. She had to be freed.

‘Marta.’

Her smile from behind Effie’s viridescent gaze was radiant.

‘Whatever happens, remember how much I love you.’

I felt her little hand creep into the warm hollow of my neck.

‘I promise it will soon be over, darling,’ I whispered, my arms around her, ‘I promise.’

I felt her smile against my skin.

‘I know, Mother,’ she said. ‘I love you, too.’

After that confrontation, my wife was the enemy: a soft shadow watching with cold, verdigris eyes as I moved through our haunted house. She had grown mantis-thin in spite of the quantities of sweetmeats she ate, drifting like a drowned mermaid through the thick green air of the gas-jets. I did what I could to avoid touching her, but she seemed to take pleasure in brushing against me as often as she could, and her touch was like winter fog. She hardly spoke to me but murmured to herself in a thin, childish voice; sometimes, as I lay awake at night, I fancied I could hear her singing in the dark: nursery rhymes and schoolyard chants and a French lullaby she had sung when she was a little girl:

‘Aux marches du palais…

Aux marches du palais…

’Y a une si belle fille, lonlà

’Y a une si belle fille…’

I spoke with Russell once more, and I allowed myself to be persuaded, with sighs and the suggestion of a few manly tears, that the only hope of a cure for my darling Effie was a spell of close supervision at some reputable hospice. I flinched visibly at the good doctor’s hint that grief at the loss of her child might have permanently unhinged Effie’s mind, but demurred when it was forcibly brought home that if I did not act soon Effie might do something to seriously injure herself. With an outwardly clouded brow and a hot, inward grin I signed a paper, which the doctor countersigned, and I tucked it carefully into my wallet when I left. On the way home I stopped at my club for lunch-for the first time in weeks-and ate ravenously. Over my glass of brandy I allowed myself the rare luxury of a cigar. I was celebrating.

It was almost dark when I reached Cromwell Square, though when I looked at my watch it was only ten past three. The wind had risen, blowing drifts of black leaves hither and thither across the roads, and I thought I felt the sting of sleet against my face as I paid the hackney and hurried indoors. A freezing catspaw of gritty wind clutched at my coat-tails as I opened the door, sending a flurry of dead leaves into the house ahead of me; I slammed the door against the dark, shivering. There might be snow tonight.

I found Effie in the unlit drawing-room, sitting beside the empty grate with her tapestry discarded across her knees. The window, absurdly, was open and the wind blew directly into the room. Dead leaves littered the floor. For a brief, nightmarish moment the old terror overwhelmed me again, the feeling of helpless diminishment, as if for all her Gothic pallor and ghostly appearance she had somehow made me a ghost in my own house, myself the wraithlike drifter and she the solid, living flesh. Then I remembered the paper in my wallet and the world reasserted itself. With an impatient exclamation and two steps forwards I rang the bell for Tabby, forcing myself to speak to Effie as I squinted at the grey blur of her face in the dark.

‘Now, Effie,’ I chided. ‘What are you thinking of, sitting here in the freezing cold? You’ll catch your death. And what is Tabby thinking of letting you stay here with no fire? How long have you been here?’ She turned towards me, a half-girl, her face bisected by the slice of gaslight from the passage.

‘Henry.’ Her voice was as flat and colourless as the rest of her. In the bizarre dislocation of her features only half her mouth seemed to move: one eye fixed mine, pupil drawn to a pinprick against the light.