Sam Callahan had lost his left eye to a piece of flying glass in Liverpool, and his right eye to the truth in Denver.

Not literally—the right eye was still there, on his face, seeing everything he wished he could unsee. But the truth had taken something from it, some brightness and some belief, until now it looked like the left one: dull, distant, fixed on a point somewhere beyond the horizon where the desert met the sky and the sky met the lie.

He stood on top of Mirror Array Twelve and looked out over the Colorado desert, where the sun was setting and the mirrors were catching the last light and throwing it back across the dunes in a thousand brilliant rays. From this height—fifty feet above the ground, on a platform of steel and glass—the desert looked like an ocean, golden and endless and full of things that shimmered just beneath the surface.

Except the shimmer wasn't water. It was sunlight. Reflected. Refracted. Manipulated.

Sam had built these mirrors. He had designed the array, calibrated the angles, polished the glass until it was the smoothest thing he had ever touched in his life. He had been proud of the work. He had told himself it was for a noble purpose: to create a solar signaling system that would help railway workers see further and safer along the Pacific Railroad's western extension.

That was what Mr. Harrington had told him, at any rate. Harrington was the director of the western division for the Pacific Railroad Company, a fifty-five-year-old man with a silver mustache and a voice like honey and eyes like the bottom of a well—dark, depthless, and full of things you didn't want to know were there.

"Mr. Callahan," Harrington had said, sitting in his office in Denver with the desert visible through the window behind him, "you are a man who understands light. You have cleaned mirrors for the great buildings of the East. You have polished glass until it sang. Now I am asking you to do something greater: to build a system that will use the sun itself as a signal, a beacon that will guide our workers along the western frontier."

It sounded noble. It sounded honest. Sam had believed him.

He was an idiot.

The revelation had come slowly, like dawn. First, Sam noticed that the mirrors were not aimed at the railway. They were aimed at the desert—specifically at certain patches of sand dunes in areas where there was no railway, no workers, no reason for the Pacific Railroad to be reflecting sunlight.

Then he noticed that those patches of sand dune, when the mirrors caught the sun at the right angle and the humidity was just right, would shimmer. Not reflect—their own internal shimmer, like water. Like a lake. Like an oasis in the middle of three hundred miles of desert.

And then he noticed the immigrants.

They came in wagons, hundreds of them, drawn from the railway towns and the mining camps and the cities of the East, carrying everything they owned in covered wagons, heading west in search of the promised land. And somewhere along the way, they had heard about the lakes in the desert—the lakes that the mirrors created, the lakes that shimmered in the distance and promised water and fertility and a place to plant a garden and raise a family and die with your feet in soil that wasn't dust.

Sam had seen the wagons. He had seen the hope on their faces as they followed the shimmer across the desert, following a mirage created by his own hands, by his own polishing, by his own calibration of angles and focus and reflectivity.

He had tried to warn them. Once, when a family of four was lost in the dunes three miles from the nearest water source, Sam had climbed to the top of Mirror Array Seven and deliberately adjusted the angle, breaking the illusion. The shimmering lake vanished, replaced by ordinary sand. The father had fallen to his knees and screamed. The mother had held her children and wept. And Sam had gone back to his room in the company boarding house and drunk himself to sleep and told himself he had done the right thing.

It hadn't mattered. The family had died two days later, dehydration and sunstroke. The company had buried them in an unmarked grave in the desert and moved on. And Sam had gone back to polishing mirrors.

Because he was a coward.

That was the truth, the one that had taken his right eye—or at least taken something from it. He was a coward who had built a machine that lied, who had watched people die because of the lie, and who had done nothing about it until it was too late for everyone who had followed the shimmer.

Deputy Marshal Reed found him six months after the family died. Reed was forty-two, a federal lawman tracking railroad fraud, and he had been following the Pacific Railroad Company for two years. He found Sam at the bar of the Laramie Hotel, sitting alone, drinking whiskey that tasted like turpentine and regret.

"Mr. Callahan," Reed said, sitting down without asking. "I know what you built."

Sam didn't look up. "There's a lot of things I built, Marshal."

"I know about the mirrors. The solar signaling system. The way you aimed them at the desert instead of the railway. The way the reflected sunlight creates the illusion of water."

Sam's hand stopped halfway to his glass. He looked at Reed and saw something he hadn't expected: not judgment, not disgust, not the look of a man who had discovered that he had been drinking with a monster. He saw recognition.

"I've been investigating this company for two years," Reed said. "Insurance fraud. Land speculation. Deliberate misdirection of immigrants to purchase worthless desert land at inflated prices. The mirrors are the centerpiece of the operation. You built the centerpiece, Mr. Callahan."

"What do you want from me?"

"I want you to testify. Before the federal grand jury in Denver. You tell them what you know, how you built the system, who ordered you to aim the mirrors at the desert, who profits from the fake lakes, and I will protect you."

Sam laughed, and it was not a pleasant sound. "Protect me? From who? Mr. Harrington? The senator who owns half the railroad? The judge who signs the land patents? The marshal who takes bribes to look the other way?"

"From everyone," Reed said. "If you testify, I can protect you."

Sam looked at him for a long time. Then he nodded. "Alright. I'll testify."

Reed smiled. It was a thin, tired smile. "Good. The grand jury sits in thirty days. Prepare your statement."

Sam prepared his statement. He wrote down everything he knew: the dates, the angles, the names, the payments he had seen, the conversations he had overheard, the families he had watched die because of the shimmer. He practiced his testimony in front of the mirror in his room, watching his own reflection and trying to believe that the man looking back at him was telling the truth.

But thirty days is a long time in the desert, and in thirty days, Mr. Harrington found out.

Harrington did not send thugs. He did not threaten Sam with violence. He did something worse: he invited Sam to dinner.

They sat in Harrington's dining room, a spacious room with a table that could seat twenty and a view of the desert through windows that were twice the size of any windows Sam had ever seen. Harrington had the same windows installed in every room of his house—floor-to-ceiling glass that turned the desert into a painting, a panorama of sand and sky and light that changed with the weather and the hour and the mood.

"Sam," Harrington said, pouring wine into two glasses and handing one to Sam. "You've been a valuable employee of this company. Your work on the mirror system has been... remarkable."

Sam held the wine glass but didn't drink. "I know what the system does."

"I know you do." Harrington sat across from him, calm, composed, the picture of a man who had nothing to hide. "And I know that you have been talking to a federal marshal."

Sam felt cold. "And?"

Harrington smiled. "And I want to offer you a choice. You can testify before the grand jury, and we will destroy you. We will buy the judge, the jury, the witnesses, the marshal, the newspaper reporters who cover the trial. You will be charged with sabotage, with conspiracy, with treason against the United States government and the state of Colorado. You will spend the rest of your life in prison, and no one will ever know the truth."

"And the other choice?"

Harrington leaned forward. "You can come work for me. Not as a mirror cleaner. As the director of the solar division. You will design new systems, new mirrors, new ways to use the sun to create value. You will be paid well—triple what you earn now. You will have a house in Denver, a carriage, servants. You will never have to climb scaffolding again."

Sam looked at him. "And the immigrants? The families who die following the shimmer?"

Harrington's smile didn't waver. "Mr. Callahan, I am not in the business of killing people. I am in the business of selling hope. The desert has no water. But the mirrors do. Is that so different from what any salesman does? You sell a product that promises something it cannot deliver. The difference is that my product is sunlight, and sunlight is free."

Sam thought about the family he had watched die in the dunes. He thought about the unmarked graves in the desert. He thought about the shimmer, beautiful and terrible, reflecting across three hundred miles of sand like a promise that wasn't real.

He thought about his house in Denver. His carriage. His servants. The end of climbing scaffolding.

He took the job.

He told himself it was temporary. He would take the job, learn the system from the inside, and then find a way to expose it from within. He told himself this for six months, while he designed new mirrors, calibrated new angles, polished new glass, and created new shimmering lakes in the desert that lured more immigrants to their deaths.

He stood on top of Mirror Array Twelve on the night Reed came to find him the second time. Reed was alone, and he looked tired, and he had bad news.

"The grand jury was dismissed," Reed said. "Harrington bought the senator who oversees the judiciary. The whole case is dead. I'm sorry, Sam."

Sam looked at the mirrors, catching the last light of the day, throwing it back across the desert in a thousand brilliant rays. He looked at the shimmering lakes in the distance, where more wagons were approaching, drawn by the promise of water that wasn't there.

"I know," Sam said.

He went back to polishing the next morning. He stood on top of the mirror array and adjusted the angle, creating a new lake, a new shimmer, a new promise. He polished the glass until it shone. He watched the wagons approach. He watched the hope on the faces of the people in the wagons. He watched the desert swallow them, one by one, like a mouth that could never be filled.

And he knew, with a certainty that would haunt him for the rest of his life, that he was no longer a mirror cleaner. He was a mirror maker. He was no longer a man who cleaned glass. He was a man who created illusions. And there was no cleaning the glass of that.