The black car smelled of new plastic and cold, careful air.
Yui sat in the back seat and held her class notebook like a small shield.
Outside the window, her town slid away into the dark, house by house.
"Where are we going?" she asked in a very small voice.
"To a place called the Listening Post," Director Voss answered from the front seat.
"It is the center for the Visitor, built in forty days."
"I'm sorry, but I think you have the wrong person," Yui said carefully.
"I am not a scientist. I teach English to seven adults in a small room."
Voss turned and looked at her for a long, quiet moment.
"Ms. Harada, we had two thousand scientists ready," she said. "It chose you."
Three hours later, the Listening Post appeared on a hill above the sea.
White buildings, tall antennas, and a thousand windows that were all still awake.
People from many countries hurried through the halls with tired, serious faces.
Every screen in every room showed the same pale point of light near the Moon.
In a quiet meeting room, a tall gray-haired man was waiting for them.
He had sharp eyes behind thin glasses, and he did not smile.
"Dr. Elias Adler," Voss said. "He leads our language team."
Adler looked at Yui the way a museum looks at a lost tourist.
"So this is the podcast teacher," he said slowly.
"Forty-three listeners. No in . Remarkable."
Yui bowed and said sorry, though she was not sure what for.
Voss led her to a wall of screens in the main control room.
"Before your , you should see our forty days," she said.
The record began to play, and it was a record of silence.
Day one: the world's best sent prime numbers into the sky.
The Visitor said nothing at all.
Day nine: music, from single drums to whole symphonies, in careful order.
Nothing came back.
Day twenty: pictures, , the songs of whales, the sound of rain.
Nothing, nothing, and again nothing.
"We tried one hundred and twelve human languages," Voss said quietly.
"The Visitor ignored every one of them for forty days."
"Then, last night at 11:47, this arrived without any warning."
On the main screen, Yui's own sign-off appeared in capital letters.
"IF NO ONE LISTENED TONIGHT, THAT'S OKAY. I WAS TALKING TO THE STARS."
And under it, one word stood alone: "TEACH."
Yui's legs felt weak, and she held the edge of the table.
"Why me?" she whispered. "My English is so simple. So slow."
Adler answered before Voss could open her mouth.
"An excellent question. Our team believes the reply is an error."
"A machine can copy a human voice. Copying is not understanding."
Voss raised one hand, and Adler stopped talking.
"Error or not, it asked for a teacher," she said.
"Ms. Harada, we will give you one . Thirty minutes. One chance."
"One ," Adler repeated. "Then the return to their work."
That night, Yui lay awake in a small guest room without a sea sound.
The room was clean and white, and it felt like the inside of a refrigerator.
She thought about her seven students, and about a boy who failed his test.
What do you say to something that crossed the dark for a million years?
Then she remembered her own classroom rule, and she almost smiled.
One sentence. Just one. And slow is perfectly fine.
In the morning, they brought her to the room.
It was cold, and it was full of quiet, breathing machines.
One hundred people stood behind the long glass wall, watching her.
Somewhere beyond the clouds, half the planet was watching too.
News helicopters circled far outside the fence, hungry for one picture of the shy teacher.
On the desk, there was a single silver microphone, thin as a flower.
"Speak normally," the chief said. "Your voice becomes radio waves and text."
"Its answers return as text, and a soft machine voice will read them."
Yui sat down in front of the microphone, and her hands were shaking.
She saw Adler's folded arms, and Voss's careful, tired eyes.
She closed her own eyes and stood in her classroom in her mind.
Nobody laughs at anybody.
Tonight, that rule was for her, too.
She leaned toward the microphone and spoke very, very slowly.
"Good evening. My name is Yui. I am a teacher."
"Thank you for listening to my show. I did not know you were there."
"You asked me to teach. I will try."
"But first, I want to say hello, the way I always say it."
She took one slow breath, and the whole room held its breath with her.
"Hello, friend."
The screens stayed dark for three seconds, then five, then ten.
Adler let out a small breath that was almost a smile.
Then every screen in the Listening Post lit up at once.
Two words appeared, in large and letters.
"HELLO TEACHER."
The soft machine voice read the words, and behind the glass, somebody began to cry.
Yui covered her mouth with both hands and could not speak.
Then, under the two words, something else appeared, small and strange.
A number.
"25."
It did not blink, and it did not explain itself.
"What does that mean?" Voss asked sharply. "Twenty-five what?"
Nobody in the room could answer her question.
Outside, on every street on Earth, people stopped walking and looked up.
The first lesson had begun, and the whole world stood still to listen.