I.

Arthur Windslum woke to the scent of beeswax and old paper, and knew things that had never happened.

The room was his--the mahogany bed, the portrait of his great-grandfather on the wall, the gas lamps his father had insisted be converted to electric last winter. But beyond the window, beyond the London fog that clung to the rooftops like a shroud, Arthur saw a city that did not exist: towers of glass and iron piercing the clouds, streets lit by a light without flame, machines that flew through the sky like metal birds.

He had always seen it. Since he was a boy of twelve, lying in this same bed with a fever, the vision had come to him unbidden. A future world. A city of gears and copper pipes and brass engines. He could describe every detail: the architecture, the machinery, the clothes people wore. He could draw the blueprints from memory.

"Another one, Mr. Windslum?"

Dr. Edmund Ashworth set his leather case on the desk and looked at Arthur with the practiced patience of a man who had spent fifteen years treating the wealthy and the delusional.

"The visions are worse tonight," Arthur said. "The towers are clearer. I can see the gears turning inside them. I can hear them--clicking, grinding, like a great clockwork heart."

"You saw them last week too. And the week before."

"I know. But they're changing. Something is--arriving."

Arthur picked up a charcoal stick and began to draw on the margin of an invoice. Lines became angles became curves became a machine unlike anything in the Royal Academy's textbooks. A device that converted steam into something else--something cleaner, more powerful. He had seen it in the future city. He had seen it powering entire districts.

Dr. Ashworth watched in silence. He had seen these drawings before. Dozens of them. Each one more elaborate than the last. Each one describing a machine that could not possibly exist.

"Arthur," the doctor said gently, "you are a brilliant man. Your designs for the railway expansion have made your family's fortune. But I must ask you again: how do you know these things?"

Arthur set down the charcoal. "Because I was there, Edmund. In that future. I lived there. And then I woke up in this body, in this time, with all the memories intact. I am a man from tomorrow, trapped in the yesterday of 1874."

The doctor said nothing. He had heard this speech before.

II.

Three months later, Arthur Windslum was the most talked-about man in London.

His steam-to-electric converter had been demonstrated at the Crystal Palace before an audience of two thousand. The machine worked--not perfectly, but well enough to convince engineers that Arthur's designs were not the fantasies of a madman, but the blueprints of a genius.

The newspapers called him "The Prophet of Progress." The Royal Society offered him membership. Prime Minister Gladstone requested a private audience.

Arthur accepted every honor with the weary grace of a man who knew he was merely remembering what others had yet to discover.

But the visions were changing.

At first, they had been clear: the future city, the machines, the streets. Then, gradually, anomalies appeared. A bridge over the Thames that did not exist--a bridge of white stone with arches of impossible elegance. A name: "The Ashworth Memorial." A name that belonged to no one.

"Edmund," Arthur said one evening in the doctor's study, "in my vision last night, there was a man. He stood on that bridge. He had your face, Edmund. But older. Sadder. He was--waiting."

Dr. Ashworth set down his glass. "Arthur, I need to show you something."

He rose and returned with a leather-bound journal--his own journal, from fifteen years ago. He opened it to a page marked with a ribbon.

"When you were twelve," the doctor said, "you had a fever. A terrible one. For three weeks, you hovered between life and death. During that time, you spoke in a language you did not know. You drew machines on the walls of your bedroom with charcoal. When you recovered, those drawings were still there."

Arthur stared at the page. The drawings were crude--childish, even. But they were the same machines he had been drawing for months. The same designs. The same impossible technology.

"I--I don't understand," Arthur whispered.

"The hospital kept records," Dr. Ashworth continued. "During your illness, you were diagnosed with a condition we have never seen before. The physicians called it 'temporal dissociation syndrome.' Your mind, under the stress of the fever, began to construct an elaborate fantasy world. A future that does not exist. A life that never happened."

Arthur stood up. "That's impossible. I remember--"

"What do you remember, Arthur?" The doctor's voice was kind but relentless. "Tell me: have you ever left England? Have you ever seen a machine that flies? A street lit without flame?"

Arthur opened his mouth. Closed it.

"No," he said. "I have never--"

"But you remember them," Dr. Ashworth said. "You remember them very clearly. Which means they are not memories, Arthur. They are dreams. Vivid, detailed, coherent dreams. And your mind has confused them with reality."

Arthur walked to the window. London lay before him--real, solid, unchanging. The gas lamps flickered in the fog. The horse carts clattered on cobblestones. A world of iron and steam and empire.

"I am not mad," he said quietly.

"No," Dr. Ashworth agreed. "You are something worse. You are a man who has built a beautiful lie, and you cannot bear to let it go."

III.

The collapse was gradual, then total.

Arthur's machines began to fail. The converters he designed sparked and burned. The engineers who had worshipped him now whispered behind his back. The Royal Society rescinded its offer of membership. The newspapers that had called him a prophet now called him a fraud.

But the worst was inside his head.

The visions grew darker. The future city crumbled. The towers collapsed into ruins of twisted iron and shattered glass. The gears ground to a halt. The clockwork heart stopped beating.

And the man on the bridge--the man with Dr. Ashworth's face--began to speak.

"You are not from the future, Arthur," the man said. "You are from nowhere. You are a man who has lost himself, and you have built this world to fill the void."

Arthur stopped eating. Stopped sleeping. He spent his days in the study, drawing on every surface: walls, floors, tables, the backs of old letters. The machines grew more elaborate, more detailed, more impossible. A city of gears and copper pipes. A civilization that existed only in his mind.

One morning, his father found him standing in the center of the room, surrounded by drawings, speaking in a language no one understood.

Arthur Windslum was committed to Bethlem Royal Hospital on a Tuesday in November.

IV.

The walls of Bethlem were white and bare.

Arthur sat on a narrow cot and drew on the wall with a piece of charcoal he had hidden in his sleeve. The machine was almost complete: every gear, every pipe, every valve. A city that would never be built. A future that would never arrive.

A nurse stood in the doorway, watching him with pity. She had seen men like him before. Men who spoke of grand designs and impossible machines. Men who had lost themselves in worlds that existed only in their heads.

"Mr. Windslum," she said softly, "it's time for your medicine."

Arthur did not look up. He was drawing a gear. A small one. It would turn the great central wheel. And the wheel would turn the city. And the city would rise from the fog like a dream made real.

"Arthur."

He looked up. Dr. Ashworth stood in the doorway. Older. Sadder. The man from the bridge.

"I brought you something," the doctor said. He held out a sketchbook. Arthur took it with trembling hands.

The pages were filled with drawings. His drawings. The ones he had made over the past year. The machines. The city. The future.

"I kept them," Dr. Ashworth said. "All of them. Every one."

Arthur turned the pages with tears in his eyes. "You kept them?"

"I know how much they mean to you."

Arthur looked at the drawings. Then at the wall. Then at the doctor.

"They're not real," he whispered.

"No," Dr. Ashworth said. "They're not."

Arthur set down the sketchbook. He picked up the charcoal. And on the white wall, he drew one more machine. A small one. Simple. Beautiful.

Then he set down the charcoal. And sat on the cot. And looked at the city he had built, gear by gear, on the walls of a madhouse in Victorian London.

Outside, the real London went on. Horse carts clattered on cobblestones. Gas lamps flickered in the fog. A city of iron and steam and empire.

And in a white room at Bethlem, Arthur Windslum sat in silence, surrounded by the clockwork dreams of a man who had never been anywhere but here.