The fog rolled off the Thames like a living thing, thick and yellow as old gin. Thomas Blackwell pulled his coat tighter and hurried down Petticoat Lane, his leather apron damp with moisture and something darker he did not care to name. He had made his second bargain that night. He could feel the absence where his father's pocket watch had been—a hollow in his chest where memory lived. He could no longer remember his mother's face.

The shop was locked, but the cat was already inside.

Blackthorn sat on the counter, velvet collar catching the gaslight, three tails arranged with the careless elegance of a creature that had never known want. He spoke with a Welsh accent that no street cat should possess.

"She is marrying Lord Ashworth on the fifteenth," the cat said.

Thomas set down his satchel. His hands were shaking. "You knew."

"I know everything worth knowing. You should have asked me sooner."

Eleanor Croft had not spoken to Thomas in three days. Not since the ball at Croft Manor, where they had danced beneath chandeliers that cost more than Thomas's entire block, and for one perfect hour, he had believed he might be worthy of her. Now he understood the cost of that hour. He had given up his shop the day after. He had given up his father's watch the night before. He was becoming a man made of holes.

"Why are you doing this?" Thomas asked. The question came out smaller than he intended.

Blackthorn's golden eyes did not blink. "Because you asked me to. Because you offered everything I required. Because you are a foolish man who would trade his soul for a woman who will never truly be yours."

Thomas wanted to strike the cat. Instead, he sat on the stool by the workbench and put his head in his hands.

The journal appeared three nights later. Thomas found it in the cellar beneath St. Dunstan's Church, where Blackthorn had told him to look. The leather binding was cracked, the pages yellowed, the ink faded to the color of dried blood. It belonged to a man named Rhys ap Gwyn, a Welsh nobleman stripped of his title in 1673 for crimes that the journal described in terms so precise Thomas felt them like physical blows.

Rhys had not been cursed by his enemies. He had cursed himself.

The final entry read: I have learned that a vessel requires three things—loneliness, desire, and surrender. The first two are easy to arrange. The third requires patience. I have waited three hundred and fifteen years. I will wait three hundred and sixteen.

Thomas sat in the cellar for a long time. The gas lamp above him flickered. Somewhere above, the city of London went on, unaware that a creature older than the city itself was preparing to wear a leatherworker's skin like a coat.

He climbed the stairs slowly. Blackthorn was waiting.

"You have read it," the cat said. It was not a question.

"What are you?" Thomas asked.

"I am what you made me. You came to me begging for help. I gave you exactly what you asked for. Tell me, Thomas—was it not worth it? The ball? The dance? The way she looked at you?"

Thomas thought of Eleanor's face in the candlelight. He thought of the way her hand had felt in his. He thought of the hollow in his chest where his mother's face used to be.

"It was worth something," he said quietly. "I just don't know if it was worth everything."

Blackthorn's tails stilled. For the first time, the cat looked uncertain.

The blood moon rose on the eighth of November. Thomas stood before his shop window, watching his own reflection—a man with a scarred cheek and hollow eyes, wearing clothes he no longer owned. Behind him, Blackthorn waited. Behind him, the cellar held a journal that proved Thomas was not a man but a vessel, a container waiting to be filled.

He turned to the cat.

"No," he said.

Blackthorn's ears flattened. "You do not have the word for it."

"I do now." Thomas reached beneath the counter and pulled out his father's old leather apron—the one thing he had not surrendered. He tied it around his wrist like a bandage. "I will not give you my soul. I will not give you my name. I will not become a ghost in my own life."

The cat hissed—a sound that was entirely feral, entirely ancient. The gas lamps in the street outside went dark, one by one.

Thomas opened the door and stepped into the fog. He did not know where he was going. He only knew he was going. Behind him, Blackthorn's voice followed him down the street, thin and furious and fading:

"You will come back. They always come back."

Thomas did not look back. He walked toward the river, toward the sound of water and the smell of salt, toward a city that did not know his name and therefore could not take it from him.

Three streets later, he saw her.

Eleanor Croft stood beneath a lamplight that should have been dark, her coat pulled tight, her face wet with rain or tears he could not tell apart. She held a letter in one hand.

"Thomas," she said. "I have been looking for you."

He stopped. The fog parted, just for a moment, and he could see her face clearly for the first time in weeks. She was real. She was here. She was his.

"I don't have a shop," he said. "I don't have anything."

"You have yourself," Eleanor said. "Is that not enough?"

Thomas looked back down the street toward his shop, toward the cellar, toward the cat who waited in the dark. Then he looked at Eleanor, and he made his choice.

"No," he said. "It is more than enough."

The lamplight flickered back on. The fog closed behind them. And somewhere in the dark, a three-tailed cat watched them go with an expression that might have been anger or might have been something the cat did not yet have a name for.