Chapter 1
The Beach
The doctors on Earth gave me ten years, fifteen if I was lucky.
That was twenty-two years ago.
Turns out 2g is a hell of a cardiac rehab program.
I was thinking about this, as I do most mornings, while walking along the shore at Tlamo. The Eridians don't call it a beach. They don't have a word for it that maps cleanly. The closest translation Rocky and I ever worked out was "the place where the heavy stops being heavy," which is poetic until you realize Eridians find poetry mildly suspicious.
The shore at Tlamo is not water. It's a slow-moving slurry of dissolved ammonia and suspended silicates that laps against black mineral sand under a sky the color of a bruise. You can't swim in it. You can't drink it. You can stand in it up to your ankles, though, and at 2g that's about all the swimming a sixty-six-year-old man needs.
I walked.
Forty minutes out, forty minutes back, every morning Erid let me. My knees complained the whole way. My knees have complained the whole way for two decades. My knees, my cardiologist back on Earth used to say, were going to be the death of me.
My cardiologist was wrong about a lot of things.
I crested the small rise at the halfway point and stopped to catch my breath. The Eridian Health Council had built a bench there for me. Just for me. The only bench on the entire planet, as far as I knew. Eridians don't sit. They don't have a sitting-shaped body. But they understood, in their precise and slightly bewildered way, that the human guest required a bench, and so a bench appeared.
A small plaque on it read, in Eridian script:
For the soft one. Rest is not weakness.
I sat.
Out across the ammonia flats, a cargo brick was descending from the orbital tether at Kemu. I watched it come down. It didn't bank. It didn't flare. It didn't do any of the things a human spacecraft does when it meets a planet. It just lowered, straight and patient, like a spider settling onto a web-strand. When it reached the platform, it stopped. No retro burn. No dust plume. It just arrived, the way a chapter in a book ends and the next one begins.
I'd been watching Eridian ships do this for twenty-two years and it still felt wrong. Not wrong like broken. Wrong like watching someone read a book by skipping to every chapter heading. They get there. They get all the information. But they're not reading the way I read. They're not flying the way I fly.
My watch buzzed.
It was Rocky's watch, technically. He'd built it for my fiftieth birthday, which was also his fiftieth birthday, because we'd agreed long ago that we'd celebrate birthdays on the same day to simplify things. It measured my heart rate, my step count, the local gravity gradient, and — for reasons Rocky refused to explain — the ambient ammonia concentration. I'd asked him once why a heart rate monitor needed to track ammonia. He'd said, In case.
The watch was telling me my heart rate was 112 and my pace was slow.
I stood up.
"Yes, fine," I said to no one. "I'm going."
The bench did not respond. The bench never responds. That's why I like it.
I walked.
Chapter 2
The Classroom
I teach now.
I didn't plan to. After the first few years, after Rocky and I had finished the work of getting Erid through the astrophage crisis, after the celebrations and the ceremonies and the slow strange decade of becoming a permanent fixture on someone else's planet, I'd assumed I would retire. Read books. Walk the beach. Die quietly at some point and donate my body to Eridian science, which Rocky had already accepted on my behalf without consulting me.
But Eridian children kept showing up at my apartment.
They wanted to know about Earth. About orbital mechanics. About what a cloud was. About why human ships pointed in the direction they were going, which Eridian children found hilarious. They came in groups of three or four, knocking politely on my pressure door, holding out small thermal pads as gifts because they'd been told humans liked warmth.
By year five, I had a classroom.
By year ten, I had a curriculum.
By year twenty, I had a reputation as the most morally superior teacher on Erid, which was a title I had not sought but which I was, frankly, suited for.
That morning — the morning Rocky came — I was teaching orbital transfer windows to fourteen Eridian children, all of whom were better at vector math than I was by age seven. Eridian children handle multivariable calculus the way human children handle building blocks. It's humiliating. I keep at it anyway, because the intuition is what they don't have. They can solve the equations. They can't feel the orbit. That's what I'm there for.
I was halfway through a sketch on the thermal slate — a Hohmann transfer from Erid to its inner moon — when one of the smaller students, a child called Threem-Threem (Eridian names are mostly rhythms; the translation software does its best), raised a claw.
"Teacher."
"Yes."
"Why do humans curve?"
"What?"
"The path." She pointed at my sketch. "It curves. Why do humans curve?"
I opened my mouth to answer.
I closed it.
I had answered this question before. I had answered it many times. The answer involves gravity wells and energy efficiency and the elegant truth that a curve is sometimes the shortest path between two points when you're falling around something massive. I had a whole lesson plan about it. I had diagrams.
But before I could begin, the classroom door opened.
Rocky was standing in it.
The room went quiet.
Eridians don't do quiet. Quiet means danger, death, or someone has miscalculated a pressure seal. The children went so still I could hear the faint click of their carapaces cooling.
Rocky's carapace was dusted with frost. His tool belt hung unevenly. One claw was tapping against the floor in a fast, nervous rhythm I had not heard in twenty-two years.
"Grace," he said.
"What happened?"
He lowered himself slightly. In Eridian body language, that's the equivalent of taking off your hat.
"We heard something."
I waited.
His translator clicked once.
"From Sol."
I felt my heart rate go up. The watch buzzed. I ignored it.
"What did you hear?"
"Better to show. The observatory. Now."
I looked at the children. They were all staring at me with their little expressionless nightmare-faces, which is what I called them affectionately and which they had decided was a term of endearment because I had failed to explain it convincingly otherwise.
"Class dismissed," I said.
Threem-Threem raised her claw again.
"Teacher. What is the pedagogical justification?"
I stared at her.
"The pedagogical justification," I said carefully, "is that I said so."
She considered this.
"That is a poor justification."
"It is the worst justification in the history of education," I agreed. "Go. Out. Read ahead. Tomorrow there will be a quiz and I will be in a worse mood."
They scattered, slowly, the way Eridian children scatter when they suspect the adults of being interesting.
Rocky waited until the last one left.
Then he said the part I already knew was coming.
"Problem."
Of course there was a problem.
There is always a problem.
Chapter 3
The Walk to the Observatory
The observatory was a thirty-minute walk from the school.
Rocky offered to call a cargo lift. I said no. I always say no. The walk is part of the cardiac rehab program. The walk is the cardiac rehab program. Rocky knows this. Rocky also knows that when I am rattled, the walk is what holds me together, and so he asked anyway, because Rocky is, despite everything, a polite person.
We walked through the lower tier of Kemu. Eridians built their cities the way they built their ships — vertically, in stacks, with each level pressure-sealed against the others. Humans look at an Eridian city and see a skyscraper. Eridians look at a human city and see, I think, a kind of beautiful confusion. Why spread out? What is the point of width? Width is where the heat escapes.
Rocky walked beside me at my pace, which is to say, slowly.
"You are quiet," he said.
"I'm thinking."
"About Earth."
"About a lot of things."
I was thinking about Earth. I was also thinking about the Eridian Health Council, who had told me three months ago that my cardiovascular readings were the best of any human they had ever monitored, with the obvious caveat that I was the only human they had ever monitored. I was thinking about my brother, who had been forty-four when I left, and who would be sixty-six now, the same age as me, assuming he was alive. I was thinking about the fact that I had not allowed myself to wonder whether he was alive in a very long time.
"Rocky."
"Yes."
"The signal. Was it old?"
"Sixteen years."
"So whoever sent it—"
"Likely still alive. Yes."
"Okay."
We walked.
The wind off the ammonia flats was strong that morning. It pushed against my coat, and at 2g a strong wind pushes hard. I leaned into it. My watch buzzed again. I ignored it again.
"Grace."
"Yes."
"Your heart rate."
"Is fine."
"Is one hundred forty-one."
"Is fine for the conversation we are about to have."
He made a sound that was either amusement or disapproval. After twenty-two years I still couldn't always tell. I had stopped trying.
We reached the base of the observatory tower. The lift doors opened. Eridians don't have stairs. Stairs are a human thing. Eridians have lifts, and ladders for the young, and at my age and gravity I am very firmly a lift person.
The doors closed.
The lift began its slow climb.
"Rocky."
"Yes."
"Whatever this is. Whatever they said. I want you to know something first."
"Yes."
"I'm not going back."
He turned his body toward me.
"I know."
"Erid is my home."
"I know."
"I just— I needed to say it out loud. Before we go up there."
"Yes."
The lift climbed. Outside the window, the city dropped away beneath us, stack by stack, the orbital tether visible in the distance like a thread connecting the world to the sky. I watched it. I thought about how a spider moves along a web.
"Rocky."
"Yes."
"If they need help. The humans. If they really need help—"
"Yes, Grace."
"—we'll figure it out."
"Yes."
The lift slowed.
The doors opened.
The observatory was dark and cold, the way Eridians like it. A bank of screens lined one wall, all showing the same waveform, scrolling slowly, ghostly and pale.
A signal.
A human signal.
Sixteen years old and still arriving.
Rocky gestured toward the main console with one claw.
"Now we listen," he said.
I took off my coat.
I sat down at the console.
I pressed play.
