Riku had always been afraid of heights.
Not a paralyzing fear — not the kind that prevented him from climbing things, from standing at edges, from living a normal life in a city built vertically. More like a heightened awareness: a clarity about exactly how far the ground was and what would happen if he stopped being where he currently was. Most people had this awareness and ignored it. Riku had it and could not quite manage the ignoring.
The walkway he landed on was glass. Clear glass, mounted on a framework he couldn't see from where he stood, suspended between two towers at a height he didn't want to estimate. Below the glass — nothing. Clouds. Then a vast, luminous void that gradually, far below, resolved into something that might have been an atmosphere.
He had exactly three seconds before the appropriate response arrived: he gripped the railing with both hands, pressed himself against the nearest solid surface — the tower wall, thank god, there was a tower wall — and did not look down.
He breathed.
Around him, the city assembled itself into sense.
It was enormous. That was the first thing. Not tall in the way of Earth cities — not buildings stabbing upward into sky — but vast horizontally, spreading in every direction across the cloud layer like a living thing that had found its footing. The towers were connected not just by walkways but by arching bridges, enclosed corridors, diagonal cables along which small vehicles moved at speed, and in the lower registers of the city, between the towers where the cloud layer thickened, illuminated tubes that pulsed with color — blue, amber, white — like the veins of something enormous and alive.
The upper city was beautiful. The towers here were all glass and pale metal, their facades embedded with moving displays that shifted through images Riku couldn't quite parse from this distance — they seemed to be data visualizations, or art, or both. The people he could see from here were dressed in white and pale gray, and they moved with the purposeful efficiency of people who have never had to wonder if there would be enough.
The lower city — the parts below the cloud line — was different. He could see down through the glass walkway, could see the towers continuing downward, and the lower they went, the darker they got, and the older. At a certain depth, the pale metal gave way to something grayer, older, and the moving displays disappeared, and the people moved differently: slower, or faster, depending on what they were running from.
Polaris City. He didn't know the name yet; he would learn it. What he knew right now was that it was a city of verticals, and that the vertical you occupied was the most important thing about you.
His first priority was to figure out where the portal back was.
His second priority — which he discovered immediately upon thinking it — was to not die.
The walkway he stood on was, he noticed, not as empty as he'd first thought. There were people at the far end of it, in the shadow where it connected to the second tower: three small figures, moving against the wall in the pressed-close posture of people trying not to be seen. And moving toward them from the tower entrance, two larger figures in white, with the deliberate stride of people with authority.
He watched for a moment, trying to assess.
The smaller figures were children. He could see that now. Two boys and a girl, none over twelve, with the particular quality of thinness that wasn't about being built lean but about not having enough. Their clothes were gray, the color of the lower city. The larger figures were security — their uniforms had a symbol on the shoulder that Riku couldn't read from here but recognized, in the way that certain symbols are legible across all contexts: this means authority.
He watched one of the security officers grab the younger boy's arm, and the boy yelped — a sound that traveled clearly through the high-altitude air — and the girl, the oldest of the three, didn't move, didn't run, just watched the officer with an expression that Riku recognized as the face of someone who has calculated all the options and found them all insufficient.
He knew that face. He'd made that face himself, many times.
There was a public display screen near the intersection of the walkways, showing the arrest — or whatever it was — in neat official text:
UNAUTHORIZED RESOURCE ACQUISITION — MINORS — GRID 7 SECTOR 4
FINE: 500 CREDITS | DETENTION: 72 HOURS | FAMILY NOTIFICATION: PENDING
Unauthorized resource acquisition. He thought about that. He looked at the thinness of the children, at the lower-city gray of their clothes, at the way the girl was holding the younger children behind her with one arm. He thought: they stole food. They were hungry and they stole food and now they are going to be detained for seventy-two hours and fined five hundred credits they don't have.
He thought about walking past.
He had somewhere to be, after all. He had a family to find, a portal to locate, a trial to complete, a mother and father and sister who were somewhere in this multiverse, alone.
The girl looked up. Across the length of the glass walkway, in the cloud-diffused light of Polaris City's permanent noon, she looked directly at him. Not pleading. Not hoping. Just observing. Cataloguing. Adding him to the list of people who had seen and walked past.
Riku thought of his father.
His father, who had sat quiet at dinner tables and answered questions about deception with the careful evasion of a man holding something enormous. His father, who — whatever he'd been carrying — had been carrying it in order to protect people. Had been trying, in his limited and imperfect way, to do the thing that needed to be done.
Riku had spent considerable time over the past two years being furious at his father's silences. He had been, he thought now, furious in exactly the wrong direction.
He walked forward.
The glass walkway vibrated very slightly under his feet — the resonance of wind at this altitude, the structure flexing as it was designed to flex — and he focused on that, on the engineering of it, which his father had taught him to notice without teaching him directly, the way good parents teach things without lectures.
"Excuse me," he said. His Japanese emerged automatically; the city translated it, somehow, into whatever language the officers were expecting. He felt this happen and found it both reassuring and deeply strange. "These children are with me."
The officers turned. The one who'd been holding the boy's arm did not release it. They both looked at Riku with the particular expression of people who are used to having authority and are deciding whether he merited a response.
"Identification," the larger officer said.
"I don't have it on me."
"Unregistered visitor." A device scanned him; it beeped in a way that suggested dissatisfaction. "You're not in any grid system. Where are you registered?"
"I'm in transit. I came through a —" He stopped. He did not know what the word for portal was here, or if it was a known concept, or if claiming interdimensional travel would help his situation. He switched tactics. "I sent them for supplies. The responsibility is mine. If there's a fine, I'll pay it."
"Do you have credits?"
"Not on me currently."
The officer looked at him with the expression of someone confirming what they had already suspected. "Unregistered visitor with no credentials who accepts liability for unauthorized resource acquisition — that's detention for you, identity verification, minimum forty-eight hours."
"Fine," Riku said.
The girl — the oldest one — blinked. Just once. A very fast recalibration.
They were led through the tower entrance and into what turned out to be a holding corridor: a long, narrow space with benches along both walls and a ceiling too low for comfort, with the chemical smell of recycled air and the particular fluorescent light of places designed for temporary occupation.
The children were separated from Riku and taken to a juvenile intake area — "standard procedure," the officer said, with the tone of someone for whom standard procedure was the beginning and end of ethical thought. Riku was put in a cell at the end of the corridor: a cube of gray paneling with a bench and a slot for ventilation and nothing else.
He sat down. He thought: forty-eight hours. He didn't have forty-eight hours. He had a family in trial environments that became permanent if the trials weren't completed, and a father in an empty Tokyo station, and a world somewhere on the other side of a portal he hadn't found yet.
He sat with this for a while.
Then the slot in the cell door opened and something was pushed through: a small folded piece of paper. He picked it up. Unfolded it. On the inside, in handwriting that was neat and small and clearly accustomed to making a lot of information fit a small space, someone had written:
YOU'RE A TRIAL PERSON. FIRST ONE TO ACTUALLY STOP IN THREE YEARS. I CAN GET US OUT OF HERE. BUT WE NEED TO TALK FIRST. — YUKI
Riku read it twice.
He looked at the slot in the door. He said, quietly: "How do you know about the trials?"
— ✦ —
The voice that came back was not a child's voice. It was low and measured and carried a tiredness that had nothing to do with age and everything to do with duration. The voice of someone who had been somewhere too long. "Because I've been in one for three years." A pause. "I'm not from your timeline. My family tried to come through a portal six months before yours. Four of us went in." Another pause, longer this time. "Only three portals opened." The silence that followed had the specific weight of an unfinished sentence — the kind that finishes itself in your chest before your brain catches up. Riku pressed himself against the door. "What happened to the fourth?" And Yuki said: "That's what I've been trying to find out."