The Mississippi ran brown and slow through the summer of 1933, the way it always ran, indifferent to the people who lived beside it and depended on it and cursed it. Ezekiel Moore stood on the bank of the river in his bare feet, the mud sucking at his toes, and watched the water move past him with the patient persistence of something that had seen worse than this and would outlast it.

Ezekiel was twenty-two, though he looked older. The sun had aged him, the work had aged him, the hunger had aged him in ways that had nothing to do with years. He lived on a strip of land his family had worked for three generations, land that was so poor it produced more weeds than corn and more debt than grain. His grandfather had bought it from a railroad company for ten dollars an acre in 1898, confident that the soil would yield what the land promised. His grandfather had died believing in promises. His father had died believing in nothing. Ezekiel was still working on the question.

The house was a small thing, two rooms and a porch that sagged to one side, held up by a post that Ezekiel had replaced three times and would have to replace three more. Inside, his mother Rose sat on a chair that had belonged to her mother, knitting something she would never finish, her hands moving with the automatic rhythm of a woman who had been knitting since she was six years old and would continue knitting after she was gone.

"You're staring at the river again," Rose said without looking up.

"It's thinking about something," Ezekiel said, and Rose made a sound that was half laugh, half sigh, and went back to her knitting.

The signal came in the form of a letter, delivered by a boy who couldn't have been older than ten and who walked up the dirt road with the letter tucked inside his shirt like a treasure. The letter was from a woman in England, a scientist, who had discovered something in the stars and wanted to share it with anyone who would listen. She had sent copies to newspapers and universities and government offices, and most of them had thrown it away. But one copy had reached a travelling salesman named Thomas Mercer, who had read it and thought it might be worth something and brought it to Ezekiel's father, who had been buying and selling everything from mules to land titles and knew a thing when he saw one, even if he didn't understand it.

Ezekiel's father had read the letter by kerosene light, his eyes moving slowly across the words, and then he had handed it to Ezekiel and said, "Read this. Tell me what it means."

The letter described a signal that had been detected by a telescope in England—a regular pattern in the cosmic background radiation that could not be natural. The woman who had detected it, an astronomer named Eleanor Whitmore, believed it was artificial. She believed that someone, somewhere, was trying to communicate with Earth.

Ezekiel read the letter and understood none of the mathematics and all of the implications. Someone was out there. Someone was calling. And the answer, when it came, was not a greeting but a warning: there were others coming, and they were not friendly, and they had been travelling for a very long time.

He showed the letter to Reverend Thomas, a black preacher who ran a small church in a town twenty miles down the road. Reverend Thomas was a large man with a voice that could fill a cathedral and a mind that refused to be confined by the narrow theology of his congregation. He read the letter in his church, surrounded by rows of empty pews and the smell of old wood and old sweat, and when he finished he sat in his pulpit for a long time in silence.

"This changes nothing," he said finally. "And it changes everything."

"What does that mean?" Ezekiel asked.

"It means we were already living in a story bigger than ourselves. Now we just know the title."

Rose read the letter too, sitting on her chair with her knitting in her lap, and when she finished she put down her needles and looked at her son with eyes that had seen too much to be surprised by anything. "We can't do anything about it," she said. "We can't stop them. We can't even understand them. All we can do is what we've always done: live here, work the land, try not to drown when the river floods."

But the letter changed things. It changed the way Ezekiel looked at the sky, which was no longer just a thing that was blue during the day and black at night but a vast empty space filled with things he could not see and could not understand. It changed the way he looked at the river, which was no longer just water but a connector, a road, a thing that led somewhere he would never go. It changed the way he looked at Rose, who sat in her chair and knitted and knitted and knitted, each stitch a small defiance against the nothing that was coming.

The floods came in the spring of 1934, as they always did, and the river rose higher than it had in living memory, swallowing the bottom fields and threatening the house. Ezekiel stood on the porch with a sandbag in each hand, watching the water climb toward the foundation, and he thought of the letter and the signal and the warning, and he thought: this is what it feels like. This is what it feels like to stand on the edge of something and know you can't stop it.

The river took the lower field. It took the barn. It took the fence that separated Ezekiel's land from his neighbour's. But it left the house standing, as it always did, as though the land itself had decided that this small sagging thing with the sagging man inside was worth saving.

After the flood, Ezekiel sat on the porch with a cup of coffee that tasted of mud and watched the river recede, and he thought about the three generations of Moores who had stood on this porch and watched this river and tried to make something grow from soil that wanted nothing to grow. His grandfather had believed in promises. His father had believed in nothing. Ezekiel was still working on the question.

He picked up his mother's knitting from where it had fallen to the ground in the flood and brought it inside and set it in her lap and sat down beside her chair and took her hand, and she looked at him with those tired eyes and smiled, and for a moment the house was warm and the river was far away and the sky was just a sky and the world was just a world and nothing was coming and nothing was leaving and everything was exactly as it had always been.

Then the moment passed, and Ezekiel went back to the porch, and the river kept moving, and the sky kept emptying, and the world kept turning toward whatever was coming, and Rose kept knitting, stitch by stitch, the way she had always knitted and would continue to knit until her hands stopped moving and the knitting stopped with them and the river kept moving and the sky kept emptying and the world kept turning and nothing that mattered could be stopped by anyone who lived beside it.