The men worked beneath the Hudson in a language of sparks and steam. Frank O'Brien stood on the catwalk above them, a rolled set of blueprints in his hand, watching the steel ribs of the Cathedral rise from the bedrock.

That was what he called it. The Cathedral. Not the official name—the official name was Project Underground Gasification, a mouthful that made the city commissioners yawn—but the Cathedral. Because this was what he had come to believe: that clean energy was a form of prayer, that the men hammering steel in the dark were its choir, and that when the thing was finished, it would lift something out of all of them. Not salvation exactly. Something close to it.

"Mr. O'Brien."

Frank looked down. The foreman was a Irishman named Patrick, fifty years old, missing two fingers on his left hand, wearing a face full of soot and good humor.

"The concrete pour is behind schedule, sir. The delivery men from Jersey are stuck in traffic on the bridge."

"How behind?"

"Two hours, maybe three."

Frank looked at his watch. He looked at the men below, sweating in the heat of the welding torches, singing a song in a language Frank didn't understand but recognized anyway—the language of men who work with their hands and know that the work matters even when no one is watching.

"Give them four hours," Frank said. "Tell them to bring coffee."

Patrick nodded and disappeared over the edge of the catwalk. Frank rolled his blueprints tighter and leaned against the railing. Below him, the Cathedral grew. It was not beautiful in any conventional sense. It was a maze of steel beams and concrete forms and ventilation shafts, a thing built for function, not aesthetics. But Frank could see its beauty. He could see the lines of force, the flow of energy, the way every beam and bolt served a purpose. He could see, in his mind, the day when the turbines would spin and the current would flow and the smoke that hung over New York like a dirty blanket would lift.

He had been thinking about lifting things for a long time.

Frank was thirty-four years old. He had been born in Boston in a small apartment on Hanover Street, the son of Irish immigrants who had arrived in 1888 with nothing but a suitcase and a determination to work. His father had died when Frank was twelve—workplace accident at the textile mill, a machine that didn't have a guard rail, a body that couldn't be recovered. His mother had taken in laundry. Frank had taken after-school jobs. He had gone to night school. He had earned a scholarship to MIT. He had graduated at the top of his class in civil engineering.

And then the war had happened.

Frank had gone to France in 1918, twenty-three years old, full of the kind of certainty that only youth and propaganda can produce. He had learned quickly that certainty was a luxury that the world could not afford. He had seen men die in mud and gas and artillery fire for reasons that would never be explained to them, only announced in telegrams delivered to their mothers in parlars that suddenly seemed very small and very far from anywhere that mattered.

He had come home with a Silver Star and a silence inside him that no amount of noise could fill.

And he had come home with a dream. Not a grand dream. Not a dream of wealth or fame or political office. A dream of something useful. A dream of building something that would outlast him and make the lives of people he would never meet a little easier, a little safer, a little less burdened by the brute fact of survival.

The Underground Gasification Project was his answer to the war. Not directly—he was not a man who believed in fixing one problem by building a monument to its opposite. He believed in fixing things by building them right. The mines were killing men. The smoke was killing men. The air was killing men, slowly, invisibly, in hospitals across the city that no one visited because the men who filled the beds worked in factories and had no one to visit them.

Frank wanted to change the equation. He wanted to reach into the earth, where coal had been sleeping for three hundred million years, and draw out its energy without destroying the men who had always been asked to do the destroying.

It was a reasonable dream. Reasonable dreams were the most dangerous kind.

Eileen found him there at dusk, standing on the catwalk with the blueprints unrolled in front of him, watching the last of the concrete trucks disappear into the tunnel behind them. She was a reporter for the Herald, one of the few women on the news desk, and she had a way of appearing beside people exactly when they needed to be seen.

"You're going to stand there all night," she said.

"I might."

"The city is going bankrupt, Frank. I don't think we have time for all-night catwalk staring."

"The city isn't going to go bankrupt."

"The mayor says—"

"The mayor says a lot of things. Most of them are wrong."

Eileen sat down beside him on the catwalk, her legs dangling over the edge, her skirt catching on a loose nail. She didn't notice. She was looking at the blueprints.

"How much longer?" she asked.

"Six months, if the funding holds."

"If?"

"Thomas Barnard controls half the city council. He doesn't want this project."

Eileen whistled softly. "The oil man?"

"The oil man."

Frank unrolled the blueprint further. It showed the full scope of the Cathedral: the central chamber where coal would be gasified underground, the network of pipes that would carry the gas to the surface, the turbines that would convert the gas into electricity, the distribution lines that would carry the current to every borough of the city. It was elegant. It was ambitious. It was, Frank believed, inevitable.

"What does he want instead?" Eileen asked.

"Oil pipelines. He wants to pipe oil from Pennsylvania through New York. He's already bought three councilmen. He's working on the fourth."

"And you?"

Frank looked at her. "What about me?"

"If Barnard wins, what happens to the Cathedral?"

"It gets buried. Literally. The excavation is deep enough that if they fill it in, it'll be gone. A steel cathedral buried in the dark. Like something out of a myth."

Eileen was quiet for a moment. Then she said, "I'm going to write about this."

"Don't."

"Why not?"

"Because the Herald won't print it."

"The Herald prints whatever pays for the press."

"The Herald prints whatever keeps the city council from shutting it down. And Barnard owns the council."

Eileen stood up. She brushed concrete dust from her skirt. She looked at Frank with an expression he couldn't quite read—part frustration, part admiration, part something else that she would never name.

"You're a fool," she said.

"I know."

"But you're building a cathedral."

"Yes."

She walked away. Frank watched her go, then turned back to the blueprints. The gas lamps along the catwalk flickered. Somewhere below him, a welding torch flared blue, then yellow, then orange, then went dark as the worker stepped back to inspect his seam.

Frank rolled up the blueprints and put them under his arm. He was tired. He was always tired. But it was a good tired, the kind that comes from using your body and your mind in service of something that exists only in your head until you make it real.

He walked down the metal stairs, past the concrete mixers and the steel beams and the men who were building something they would never use, for people they would never meet, in a city that would probably never know their names.

He walked down into the dark, carrying the blueprint of a cathedral that didn't exist yet, believing, as he had always believed, that belief was the most practical engineering tool of all.

He was wrong about that. But he was not wrong about the rest.

The Cathedral rose. The turbines spun. The current flowed.

And Frank O'Brien died in it, three years later, when a fault line that no geologist had predicted opened beneath the Hudson and swallowed the central chamber whole. He chose to stay behind when the walls began to crack, closing the emergency valves one by one, buying time for the two hundred men on the surface to escape.

They called him a hero in the papers. Eileen wrote the story. It ran on page twelve, beneath an advertisement for Barnard's oil pipeline.

But the current kept flowing. The Cathedral kept working. And sixty years after Frank died, when a young engineer named Margaret Chen stood in the control room and watched the turbines spin and thought, This is what my grandfather meant when he said America was built by people who never got to see their work finished—

the Cathedral was still there. The steel was still strong. The energy still flowed.

Frank's dream had outlasted him. It had outlasted Barnard, whose name no one remembered. It had outlasted the city councilmen, the mayor, the newspaper editors, the men who had laughed at his blueprints and called him a dreamer.

Dreams are not the most practical engineering tool.

But they are the only ones that matter.