The heat in Jackson, Mississippi did not simply sit on you—it pressed down, heavy and wet and ancient, like the weight of something that had been buried and dug up and buried again until the earth itself forgot what was supposed to grow there. Elias Thompson wiped his forehead with the back of his hand and felt the salt crust his skin, and thought about the cotton fields his grandfather had worked, and the cotton fields his father had worked, and the cotton fields that were now parking lots and grocery stores and places where men like Elias could drive a cab and earn seventy-five cents an hour and sit in the back of restaurants and drink coffee from cups that said WHITE ONLY in letters so small you had to squint to see them.

It was July 1955, and the heat was the kind that made men violent and women invisible and boys who would become men practice their faces in the mirror, trying to look like something the world would respect.

Elias was driving back from dropping off a white family at the train station when he saw them—three men in white shirts and dark trousers, dragging a girl toward a black sedan parked in the shadow of a cotton warehouse that hadn't processed cotton in twenty years. The girl was young, maybe nineteen, with dark skin and wide eyes and a mouth that was open in a scream that no one was hearing.

Elias felt something move in his chest. Not courage—he didn't have courage. He had something worse than courage. He had the habit of doing the right thing in a world where the right thing got you killed.

He pulled his cab to the curb across the street and watched. The three men were white, and they were strong, and they were moving the girl with the kind of efficiency that told you they had done this before. The girl kicked and fought and screamed, but her voice was small against the heat and the distance and the indifference of a city that had learned not to hear.

Elias looked at the cab beside his, where an older black man sat smoking a cigarette and watching the world go by with the tired eyes of a man who had seen too much and understood too little. Elias knew him—Isaiah Brooks, who had driven a cab for thirty years and who had also driven three young men out of town in the dead of night when the phones started ringing and the names started coming in.

Elias rolled down his window. "Isaiah," he said, quiet enough that the white men couldn't hear. "I need to strike a light."

Isaiah didn't look at him. He took a long drag from his cigarette, held it, and exhaled slowly into the heat. Then he nodded, once, and reached into his pocket and pulled out a box of matches and held it up.

Elias reached over, took a match, and struck it against the side of the box. The flame was small and yellow and almost invisible in the sunlight, but it was enough.

Isaiah put the match in his mouth like a cigarette, started the cab, and drove two blocks down the street, where he pulled over and called in on a phone booth that he had paid fifty dollars to have wired directly to a man in Atlanta who had connections to a man in Washington who had connections to the kind of people who could make trouble for men like the three dragging the girl across the hot pavement.

Elias watched from his cab. He watched the girl being pushed into the sedan. He watched the men get in. He watched the car drive away. And then he watched Isaiah come back, his face unreadable, his eyes looking at Elias for the first time in thirty years of driving next to each other at the cab stand.

"What did you do?" Isaiah asked.

"I asked for a light," Elias said.

Isaiah nodded slowly. "You asked for a light. That's what you did."

Three days later, Elias learned the truth.

The girl's name was Clara Washington, and she was not the victim he had imagined her to be. She was nineteen, yes, and she had been dragged into that car, yes, but not by men who wanted to hurt her. By men who wanted to talk to her. Men who had come from Chicago and New York and Memphis, men with accents that sounded different from the South, men who wore suits and carried notebooks and asked questions that made white men in Jackson nervous.

Clara Washington was a informant. She had been working with a group of civil rights organizers from outside the state, giving them information about the meetings, the names, the places where black men and women gathered to talk about things that were not supposed to be talked about. The three men in white shirts had been undercover agents, trying to get close enough to identify the organizers, and Clara had been playing both sides, taking money from both, trusting no one, surviving in the only way she knew how in a world that offered women like her no choices at all.

Elias's signal had triggered a response from Atlanta, and the response had been to pull the agents out of the field, which meant that Clara had been exposed, which meant that she had nowhere to go and no one to trust, which meant that within a week she had left Jackson and would not be coming back.

Elias sat in his cab after he learned all of this, and he thought about the match he had struck, and the flame he had seen, and the chain of events that had been set in motion by a gesture that had seemed so simple, so clear, so right.

He had done the right thing. He knew that. And the right thing had not saved anyone.

Isaiah pulled up beside him in his cab. "You did what you had to do," Isaiah said.

"I didn't know what I was doing," Elias said.

"That's the thing about doing the right thing in this world," Isaiah said. "You never know what you're doing until it's too late."

Elias looked at his hands. They were steady, but they felt heavy, like they carried something he could not put down.

"Next time," he said.

Isaiah smiled, a small tired smile. "There won't be a next time. Not the way you're thinking. But there will be other times. And you'll know what to do."

Elias drove home through the heat of the Mississippi afternoon, through streets where white children played in front of houses with wide porches and black children walked to school with their books held tight against their chests, and he thought about matches, and about light, and about the terrible weight of doing the right thing in a world that was built on wrong.

He went inside his small house on Lynch Street, and he sat in the dark, and he struck a match, and he watched it burn, and he let it go out.