The fog that winter of 1888 did not merely settle upon London; it consumed it. Arthur Winchester stood at his study window in the Cambridge college, watching the grey curtain swallow the cobblestones below. Three years. Three years since Isabella had been taken to Bethlem, and two since the pneumonia carried her away. The letter from the hospital matron had arrived on a Tuesday, delivered by a boy whose boots squeaked against the wet flagstones. Arthur had read it twice, folded it, and placed it in the drawer beside his papers on traumatic memory and dissociative identity.

He was thirty-one, lean and pale, with the careful hands of a man who spent his days turning other people's minds inside out. Freud's theories had made him a name in academic circles, but names meant nothing to a man who had watched his younger sister's eyes go flat and distant behind the barred windows of a madhouse.

Isabella had been different from the beginning. Where Arthur was careful, she was wild. Where he spoke in measured sentences, she spoke in laughter and sudden silences. She had been twenty-eight when they took her, diagnosed with romantic madness, a fashionable term for a woman who saw too much and felt too deeply. Arthur visited every Sunday. He brought books, flowers, sometimes a small music box. She always sat by the window, her hands folded in her lap, and repeated the same words: Arthur, the Obsidian Hall is calling you.

He had dismissed it as the ravings of a broken mind. Until the night he opened her leather-bound journal.

The journal had been packed in a box from Bethlem, along with a shawl that still carried the faint scent of lavender and sickness. Arthur sat at his desk, the candlelight throwing long shadows across the room, and turned the pages. Most were blank. The last page, however, bore a single sentence in Isabella's looping hand: If you are reading this, you are ready. The one who draws the Ace of Spades must enter the Obsidian Hall.

Clamped between the final pages was a card. Black cardstock, heavy and cold. The Ace of Spades, but instead of a number, an eye had been stitched into the surface with silver thread. Arthur's fingers touched the embroidery, and the world dissolved.

He awoke on a floor of black marble. The ceiling above him was a vaulted Gothic arch, and the walls were lined with mirrors that reflected not his image but fragments of other people's faces: a woman weeping, a child reaching, a man screaming silently. The air smelled of old stone and something else, something metallic and sweet, like the scent of blood on a winter wind.

A voice spoke from everywhere and nowhere. It was neither male nor female, neither warm nor cold. It simply was. Isabella Winchester's consciousness is trapped within this hall, it said. You may retrieve her fragment by fragment, through the Soul Games. Each game yields Soul Imprints, silver coins that carry the vitality of a single mind. Accumulate enough, and she will be whole again.

Arthur's first instinct was to laugh. His second was to examine the voice with the precision of a man who had spent his career dismantling delusions. He was a scientist. This was a dream, or a hallucination brought on by grief and exhaustion. But the marble was cold beneath his palms, and when he looked down, his fingers bore a faint silver mark, like a brand.

The first game was a memory constructed from the mind of a young woman named Eliza, a governess who had watched her employer's children die of fever. Arthur entered the memory as a visitor, a silent observer. He saw her grief, her guilt, her desperate need to believe that something she had done or failed to do had caused the deaths. Arthur used every technique he knew. He found the crack in her psychological armor -- a repressed memory of a single afternoon when she had left the children alone to take a walk in the garden. He pressed on that crack. He whispered the right words at the right moments. He made her believe, completely and utterly, that she was responsible.

When the memory dissolved, a silver coin appeared in Arthur's hand. One Soul Imprint. He felt a surge of something that was not triumph but was close enough to it that he did not bother to distinguish between them.

He played many games. A soldier haunted by a order he had given that led to thirty deaths. A merchant who had bankrupted his employees to save his own fortune. A mother who had loved one child more than the others and watched the neglected one wither. Each time, Arthur found the crack. Each time, he pressed. Each time, a silver coin appeared.

As the coins accumulated, something began to shift. Each time he retrieved a fragment of Isabella's consciousness, a memory surfaced in his own mind -- not his memory, but hers. A murder. A woman on the floor of a study, blood spreading across the Persian rug. A man standing over her, his face turned away. Arthur recognized the study. It was his father's study. And the man -- he could not see the face, but he knew the posture. He had seen that posture a thousand times.

Arthur stopped counting the coins. He had reached a number that was sufficient, or close to sufficient. The Obsidian Hall opened before him a great chamber lined with mirrors, and in the center of the chamber, on a pedestal of black stone, sat a figure.

It was Isabella.

Or rather, it was the shape of Isabella. Her face was correct -- the wide eyes, the small mouth, the distinctive curve of her left eyebrow. But her body was wrong. It was constructed of black silk and silver thread, stitched together with meticulous precision. Her joints were articulated with tiny silver hinges. Her eyes were glass beads, painted with the exact shade of brown that had been her own.

On the chest of the puppet, embroidered in silver thread, were the words: Obsidian Hall.

The voice spoke again. Isabella Winchester died of typhoid three years ago. The sister you remember, the visits, the words, the music box -- all of it was constructed by your own grief and your own psychological expertise. The Obsidian Hall used your knowledge to create a puppet that would guide you. You have been manipulating minds, collecting Soul Imprints, for a soul that does not exist.

Arthur looked at his hands. They were beginning to change. His fingers were thinning, becoming translucent. Beneath the skin, he could see the black silk and silver thread. His body was unraveling, dissolving into the same materials that had constructed the puppet on the pedestal.

You are the puppet, the voice said. You always were.

Arthur tried to speak. He had a thousand things to say. He had questions, accusations, pleas. But his mouth was already silk, his tongue already thread. The last thing he perceived was not sight or sound but the sensation of being folded, carefully and precisely, into a small black box.

And in the visiting room at Bethlem, the nurse made her daily rounds. She stopped at Isabella's door and listened for a moment. The room was quiet. Isabella sat by the window, her hands folded in her lap, her glass eyes reflecting the grey London light. Occasionally, she would turn her head toward the door, as if expecting someone.

"Mr. Winchester is not coming today," the nurse said softly. "But he will come tomorrow. They always come tomorrow."

Isabella did not answer. She never did. She simply sat, a beautiful thing made of silk and thread and silver, waiting for a brother who had already been folded away.