The pounding was Kenji's.
He could feel the portal mechanism on his side of the boundary — could feel it the way you feel a door mechanism when you know the construction of it, the weight of it, the specific tolerances between the parts. It had failed to open. Not completely — it was stuck, jammed in a state between active and inactive, its resonance field half-formed, which was worse than either fully open or fully closed because it was actively consuming energy from the system without producing transit.
He stopped pounding. Pounding was instinct; instinct was useful but not sufficient.
He thought.
"The mechanism," he said to the station walls, to the voice that was still, barely, operational. "What failed?"
"The anchor's deterioration created a feedback loop in the transit resonance system." The voice was rougher now — not distorted, but strained, the voice of someone speaking through effort. "The portal can't complete activation because the anchor field that it anchors to is fluctuating. It needs a stable base frequency."
"Which the anchor used to provide."
"Yes."
"And there's nothing on this side that can substitute?"
A pause. "There's one thing."
He waited.
"The secondary portal. Dr. Saito's." The voice struggled momentarily; he heard it in the static, in the quality of the silence behind the words. "If a second anchor comes online before the primary anchor fails, it creates a brief stabilization window. Long enough for the stuck portal to complete activation."
He turned. Dr. Saito was already standing up, already closing her red notebook, already looking at him with the expression of someone who has heard a calculation and arrived at the same answer he has.
"The second anchor has to come online now," she said.
"Yes."
"Which means —"
"Now," he said. "Right now, not when the trial ends, not when the system is in better shape. Right now."
She looked at the station around them — the golden light, the honest bones of the building, the departure boards showing her city. She had not been here long, but the station had given her something she recognized: a space that was exactly what it was, with no pretense in its architecture.
"How does it happen?" she asked.
He looked at the station voice — looked at the walls, because that was where the voice came from. "You have to tell it," he said. "You have to say it out loud. Consent has to be explicit. That's —" He stopped. "That's one of the things I should have understood from the beginning. The anchor has to choose. The capacity can't be drafted; it has to be offered."
Dr. Saito looked at him for a moment with the direct gaze he had come to associate with her assessment mode — the way she looked at data before she committed to a conclusion.
"I want you to understand something first," she said.
"Tell me."
"I'm not doing this because I have nothing to lose. That's not — that's not the frame I want to put on it." She paused. "I have something to gain. The system stays up. More families move through. The neighborhood this girl came from —" She nodded toward where Tomoko had been standing before, now back on her side of the door, running toward Koto Ward to mark the Sumida River coordinates. "Her neighborhood. My city. Fifty families per window, you said. Multiply that across multiple windows before the earthquake." She looked at him. "That's not nothing. That's the thing I've been trying to do for fourteen months in every way that wasn't this. And this is the way that works."
"You could still find another way," he said. "You're extraordinary. You'd find —"
"There are seventeen minutes," she said. "Let me do this while there's time."
He nodded. He could not speak, exactly. He nodded.
Dr. Yumi Saito turned to face the center of the empty station. She stood in the golden light with her red notebook under her arm and her field jacket and her fifteen years of geological data and her specific, irreplaceable understanding of what was under the earth.
"I consent," she said, clearly, to the air of the station, to whatever was listening. "Second anchor. Voluntary. Indefinite. I understand what it means and I choose it."
For a moment, nothing happened.
Then the station changed.
Not dramatically — the building didn't shake or glow or announce itself. But the golden light shifted, deepened, took on the quality of something that was not just illumination but presence. And from somewhere in the structure — from the walls, from the high domed ceilings, from the marble floors — a sound that was not quite music and not quite speech but contained elements of both: acknowledgment.
Dr. Saito put one hand flat on the nearest column. She closed her eyes. When she opened them, something had changed in them — not in their color or their focus, but in their depth. The same thing he'd seen in his own eyes in mirrors for four years, he imagined. The quality of someone who is now connected to something larger than themselves, who can feel the edges of a system they are now part of.
"Oh," she said softly. "It's big."
"Yes."
"The other anchor. Your other self. He's —"
"Exhausted."
"Yes. He's been holding this alone for —"
"Four years."
She was quiet for a moment, in the way of someone receiving information in a channel they haven't had before, processing it in real time. Then: "The portal. Try it now."
Kenji turned to the boundary between the trial environment and the nexus. The stuck portal — he could feel it differently now, feel the ground frequency it was struggling to anchor to, feel that frequency stabilizing as the second anchor came online, the feedback loop disrupting and the mechanism freed.
He pressed his hand to the membrane.
It opened.
On the other side: white. Vast and present and inhabited.
He stepped toward it.
"Kenji."
Dr. Saito, behind him. He turned.
She was standing in the golden station light with her notebook and her field jacket and the new depth in her eyes, and she looked — not happy, not unhappy, but settled. The expression of a person who has arrived at the thing they were going to do.
"When you get to the other side," she said, "and you build the expansion. The Sumida River window. The second transit system." She smiled briefly, the focused, private smile of someone who has just accessed a database they haven't had before. "I'll send you the coordinates. Through the system. I can do that now."
"I know."
"Save the neighborhood."
"I will."
He went through the portal.
— ✦ —
The white of the nexus received him. He felt it before he saw them — his family's presences, the specific frequencies of the four people he knew best in any universe, all of them here, all of them intact. He looked up and there was Aiko, and there was Riku, and there was Hana — and two others, a girl with old eyes and a boy who shared them, standing slightly apart with the careful posture of people who are aware they are somewhere they weren't expected. His family was assembled. Three of them crossed the space to him at the same time, which was not graceful and he didn't care, and he held them in the imperfect, overcrowded way that families hold each other after things that nearly didn't work, and for thirty seconds the nexus held all of them. Then it spoke: "All four primary trial members are present. Nexus destabilization continues. Final transition window: nine minutes." Nine minutes. He pulled back from his family and looked at the nexus — at the white space that was thinning at its edges, at the strain that was visible now in the field, at the portal to the destination timeline that should be forming. It was not forming. It should have been there — the gateway to the new Tokyo, the safe world, the destination of three years of planning. It was not there. "Why isn't the final portal opening?" he asked the nexus. A long, terrible pause. The nexus spoke, and its voice had the quality of something delivering information it has calculated cannot be withheld. "There is a fifth member of your family in the system." Kenji looked at his wife, his son, his daughter, all present, all here. "There are four members of my family." "There were four," the nexus said, "when the trial began. The system has since identified a fifth signal. Related resonance. New entrance point." His children looked at each other. His wife looked at him. And from the direction of the most recently opened breach in the nexus's boundary — from the direction no one had come through yet — a portal that none of them had seen before began to open. And through its growing light, a voice said: "Dad?"