The announcement had gone up on a Monday.

  Special Assembly — Thursday, Period Three. Attendance Mandatory. Guest Presenter: Aethon Cultural Exchange Program.

  Yuji had read it on the board outside the gymnasium and then read it again and then looked at Daichi, who was already vibrating with the specific energy of someone who had been given permission to be interested in something.

  "An actual one," Daichi said. "Coming here. To our school."

  "It says cultural exchange."

  "Right, but—"

  "It says program." Yuji looked at the notice again. The paper was standard school announcement paper, the same cream color as every club recruitment flyer and exam schedule and field trip permission slip he'd seen for three years. The ordinariness of the medium felt slightly at odds with the content. "Cultural exchange programs usually involve students from other schools. Maybe other countries. Not."

  "Not other planets," Daichi finished, with barely concealed delight.

  "I was going to say not other species."

  "Same thing." Daichi was already pulling out his phone, already looking up whatever there was to look up, which Yuji suspected was not much because he was sure the Aethon or at least the government were careful about what information existed publicly. That carefulness was itself a kind of information. "This is historic. This is happening at our school. Do you think it'll be the same one from the press conferences?"

  "I have no idea."

  "The one with the weird eyes."

  "They all have the eyes, Daichi. That's kind of racist..."

  "You know what I mean."

  He did. The primary diplomatic representative — the one who had appeared at the first press conference and most of the subsequent ones, who had the particular quality of something that was being very deliberate about how much of itself it revealed in public. It had a name in the official documentation, a string of sounds the translation program rendered as something close to Ael, which the representative had indicated was an acceptable approximation without confirming it was accurate.

  He went to class. He thought about the notice.

  Thursday came with the specific atmosphere of a school day that everyone knew was going to be different — a restlessness in the corridors, an above-average number of people checking their phones, teachers with the slightly heightened alertness of people who had been given instructions they weren't entirely sure about. Yuji's homeroom teacher had told them, twice, to ask respectful questions if there was a question period, and had then said actually perhaps direct your questions to me first in a way that suggested the school administration was slightly nervous.

  The gymnasium was full by the time Yuji got there. He found a seat three rows from the back, which was where he preferred to be — far enough to see everything, close enough to hear. Daichi dropped into the seat beside him with the focused anticipation of someone attending a concert.

  The representative arrived without announcement.

  That was the first thing — no introduction, no buildup, no teacher walking to the microphone to say please welcome. The side door opened and the Aethon representative walked in and the gymnasium went quiet in the complete way that large spaces went quiet when something happened that nobody had a script for.

  It was not the one from the press conferences. It was younger — Yuji had no real framework for Aethon age, but there was something about its bearing that read as younger, less practiced, the deliberateness less polished. It was approximately human-height, which he knew was a common characteristic among the diplomatic delegation and suspected was not a coincidence. The features were arranged in the bilateral symmetry that read as face from a distance. The eyes, at this distance, were the particular color that had no name in any human language he was aware of — something between silver and the moment before lightning, catching the gymnasium lights differently than eyes were supposed to catch light.

  It walked to the front of the room and looked at them.

  "Hello," it said. Its Japanese was perfect, which should not have been surprising and was anyway. "My name is — " a pause, brief and deliberate — "Sael. I'm here to talk to you about a new form of energy we have discovered which anyone can harness, It is called flux."

  The presentation was an hour long.

  Yuji took notes. Not the notes he was supposed to take — not the ones that would appear on whatever assessment the school had presumably planned around this — but his own notes, in his own shorthand, in the small notebook he kept in his left jacket pocket that had nothing to do with school.

  Sael explained flux the way the Aethon explained most things in their public communications: accurately, thoroughly, and with a precise selection of what to include and what to leave out that had the quality of a decision rather than an oversight. Flux was energy. It permeated all of space. It was the underlying mechanism of both what humans called technology and what older civilizations had called, at various points in their histories, magic, divine power, the breath of the universe. All of these were the same thing viewed from different angles of understanding.

  It could be perceived, with training. It could be used, with more training. The capacity to interact with flux was universal among biological organisms — every living thing was a flux conductor, every living thing both absorbed and expended flux as part of its basic metabolic function.

  But... why were they teaching highschoolers this. If all he said was true doesn't that mean if well trained with flux we could become like super soldiers or something.

  The gymnasium listened with the silence of three hundred teenagers who had been told all their lives that the universe was comprehensible through physics as they understood it and were now being informed, politely and thoroughly, that physics as they understood it was a regional dialect.

  Ensure your favorite authors get the support they deserve. Read this novel on the original website.

  Sael answered questions for twenty minutes after. The questions were mostly what Yuji expected — can you do flux things right now, what does it feel like, is it like magic, can humans learn it — and Sael answered them with patient precision that revealed almost nothing about what it thought of the questions.

  Yuji did not raise his hand.

  He watched Sael instead, the way he watched things when he was trying to understand them rather than just observe them. Watched the way it moved through the question period — which questions it answered fully, which it answered briefly, which it answered by asking a clarifying question that redirected the conversation. It was good at this. It had the ease of something that had done it many times and knew exactly where all the edges were.

  He wrote in his notebook: Why here. Why schools. Why now.

  He underlined why now twice.

  After the assembly Daichi talked about it for the entire lunch period with the sustained enthusiasm of someone who had received exactly what they wanted from an experience and wanted to process it out loud. Yuji ate his rice and listened and contributed occasional sounds of agreement that kept the conversation moving without requiring him to engage with it directly.

  "The flux perception thing," Daichi said, for approximately the third time. "That's the part that gets me. It's already in us. We just can't access it without training. That's — that's wild. We've been walking around with this thing our whole lives and didn't know."

  "Mm," Yuji said.

  "You're not impressed."

  "I'm thinking."

  "You're always thinking. It's the same face." Daichi pointed his chopsticks. "What are you thinking about."

  Yuji considered how much to say. Daichi was his closest friend and reasonably perceptive and had the significant advantage of not being connected to his family's proximity to the diplomatic program, which meant he hadn't spent months accumulating small pieces of information that didn't fit together cleanly. His perspective was useful precisely because it was uncontaminated.

  "Why schools," Yuji said.

  Daichi lowered his chopsticks. "What?"

  "The cultural exchange program, the teaching teenagers about this flux thing. Why schools specifically. Why students." He looked at the table. "If you wanted to introduce flux to humanity — to the general public — Documentaries. Academic publications. You'd go through the existing channels of information. That's what they've been doing for months." He paused. "Schools are different. Schools are where you teach people things they're going to need."

  Daichi was quiet for a moment. This was unusual enough that Yuji looked up.

  "I think we have different definitions of school but you seem right. You think they're preparing us for something?" Daichi said.

  Yuji picked up his chopsticks. "I think it's worth asking what for."

  Daichi looked at the table. Out the window. Back at Yuji. "That's — I mean, that's a big leap from one school assembly."

  "It's not one school assembly." Yuji had checked, the night before, after the announcement went up. The Aethon cultural exchange program had visited forty-seven schools across six countries in the past two months. The curriculum materials distributed by the diplomatic liaison office — his mother's office, the one she didn't discuss specifically — included a new science unit on fundamental energy theory that bore a significant resemblance to what Sael had just presented. "It's a program. It's coordinated. It's moving fast for something that's supposed to be cultural."

  Daichi was quiet again, longer this time.

  "That could still be fine," he said, finally. "Introducing new knowledge. Expanding human understanding. That's not—"

  "No," Yuji agreed. "It's not necessarily anything. I'm just noting the shape of it."

  He went back to his rice. Outside the cafeteria windows it was overcast, the particular flat gray of late autumn pressing down on everything. A group of first-years were crossing the courtyard in their coats, heads down against the wind.

  He thought about flux. Thought about the assembly, about Sael explaining that every biological organism was already a flux conductor, that the capacity was universal, that it could be developed with training. Thought about the forty-seven schools and the curriculum materials and the carefully selected information and the things that had been left out — he'd noticed what was left out, had been cataloguing it in the back of his mind while Sael answered questions. Nothing about conflict. Nothing about what flux could be weaponized into. Nothing about the Igos, which he'd read enough declassified diplomatic summaries to know existed, which were apparently a significant enough presence in galactic space that every spacefaring civilization had a classification system for them.

  Introducing flux. Introducing flux perception. Introducing the foundational knowledge that everything else built on.

  He thought about what you built, on a foundation like that.

  He went home the long way.

  The notebook came out at the kitchen table, which was where he thought best — the kitchen was functional and well-lit and his mother's organized presence was in it even when she wasn't, which was grounding in a way he didn't examine too closely. He opened it to the page he'd started with, months ago, in the convenience store after the documentary, the page that had one line on it:

  Anomalous flux event — Sol system — timestamp aligns with —

  He'd stopped there the first time. He looked at it now. Then he turned to the page from today and read what he'd written during the assembly and added to it in the margins over lunch.

  Why here. Why schools. Why now.

  Flux — universal biological capacity. Training required. They're providing the training.

  Not information. Preparation.

  He paused. Tapped the pen against the page. Wrote carefully, in smaller letters beneath the rest, the thing he'd been thinking around all afternoon without quite saying to himself directly:

  For what kind of preparation do you need an entire planet's learning population to understand flux.

  He looked at it for a while.

  He closed the notebook. Put it back in his jacket pocket. Got up to start dinner.

  His mother came home at seven, tired and quiet, with the particular quality of tired that meant her day had been full of things she wasn't going to talk about. He had made rice and miso soup, which was easy and reliable and she always appreciated it. They ate together at the kitchen table and she asked about school and he told her about the assembly, watching her face while he described it.

  She listened. Her expression did what his mother's expression did when she was being careful — present, attentive, giving nothing that she hadn't decided to give.

  "Interesting," she said, when he finished. "What did you think of it?"

  "Educational," he said.

  She looked at him. He looked at his soup. They understood each other, in the way they understood each other about most things — imperfectly, carefully, with a lot of space left around what wasn't being said.

  "The soup is good," she said.

  "Thanks," he said.

  They finished dinner. He washed up. He did not ask about the curriculum materials or the forty-seven schools or the diplomatic liaison office's role in coordinating any of it, because there was a version of that conversation that went somewhere useful and a version that didn't and he didn't yet know which version they were in.

  He went to his room. Took the notebook out of his jacket. Set it on his desk.

  Looked at the photograph on his desk — the same one from the refrigerator, a smaller copy he'd put there without thinking about it much, almost two years ago now. His sister making a face at the camera. Sixteen.

  He thought about flux. About universal biological capacity and training and preparation. About an anomalous flux event in the Sol system two years ago that appeared in a government archive cross-referenced with the first contact event.

  He thought about his sister, who had been a person who walked to school one Tuesday in May and did not arrive, and who the official record described as missing, and whose case had produced nothing, and who he had made his peace with losing in the way that peace was sometimes a thing you built because you had to live somewhere.

  He put the notebook in his desk drawer.

  He went to bed.

  He did not, for once, not think about her. He thought about her directly, which he almost never let himself do, and the thinking was sharp and clear and didn't resolve into anything useful, and after a while he was just lying in the dark thinking about flux and his sister and the shape of things that didn't fit together yet.

  Eventually he slept.