The maintenance session ran forty-five minutes.

He had structured it differently from the extended sessions — not pushing for reduction, just holding the current level and confirming that the hold was stable at suppressed output rather than active effort. Mien had understood without being told: she stood in the center of the room, shoes off, and maintained thirty-four point eight percent for forty-five minutes without the number moving more than half a point in either direction.

He noted it in the log. Stable. Below target threshold. Sustainable.

She opened her eyes when he said: "Done."

"Same as yesterday's end point," she said.

"Yes. The overnight decline has plateaued. You're holding at thirty-four point eight without a session."

She looked at the number for a moment. "That's the baseline now."

"Yes."

She went to make tea. He went back to the contingency plan — fourth version, long-term assessment included — and ran through the scenarios one more time against the updated numbers. Thirty-four point eight was below Dieu's observed classification threshold. Whether it was below an enhanced scanner's threshold was an unknown he was still working to quantify.

He had two data points: the gen-3 portable scanner had returned 34% confidence at forty point one percent ambient output. The enhanced equipment Traffic was likely to deploy would have a classification threshold somewhere in the twenty-five to thirty-five percent range.

Thirty-four point eight was in that range.

He needed it lower.

He made the note. Considered the practice timeline. Tomorrow's session — if the passive decline resumed alongside active sessions, thirty percent was achievable within forty-eight hours. Just within.

He saved the plan.

They ate breakfast. The particular silence of two people running numbers in parallel, neither of them performing a calm they didn't feel, both of them holding a steady attention on what was in front of them. He had noticed this about her — the absence of performed equanimity. She was not calm because she had decided to be calm. She was simply present in what was happening, which was a different thing.

Outside, the day was developing into the kind of morning that could belong to any of the past fourteen days.

He drank his tea. He checked the time. He waited.

---

The camera flagged her at fourteen-oh-seven.

No alert from the System's approach detection — she wasn't carrying equipment the System could read at range. The flag came from the standard security camera at the market entry point: a woman in civilian clothes, hair pulled back, walking through the stall row with the particular quality of someone who had been to market before and knew what she was looking for.

He recognized Dieu in the second frame.

"Camera, market entry," he said. "She's there."

Mien was at the desk. She stood immediately and moved to the south window — three feet back, far enough to not be visible from street level.

He pulled the camera feed to the main monitor.

Dieu was buying vegetables from Mrs. Nam's stall. He could see them talking — Mrs. Nam in her element, the animated gestures of someone explaining something about the produce, Dieu listening with the attentiveness of someone who was genuinely receiving the information and filing it alongside other information she was simultaneously receiving about Mrs. Nam herself. He watched Dieu's gaze: it moved across Mrs. Nam's face, to the stall layout, to the other vendors, to the residents passing by, and back — cataloguing, cross-referencing, building a map.

"She's learning the social architecture," he said.

Mien, from the window: "How long has she been at it?"

"Maybe ten minutes before the camera picked her up." He paused. "She talked to Miss Hoa."

"I saw."

He looked at the feed. Then at Mien's profile from across the room.

"She's doing what you did," Mien said.

He looked back at the camera. She was right. The way Dieu moved through the market — noting, building, mapping without appearing to map — was the same quality of attention Mien had brought to the courtyard on morning five, to the social dynamic in Mrs. Nam's room on day nine.

"Different purpose," he said.

"Same method."

He didn't disagree.

---

Dieu reached the C-7 gate at fourteen-twenty-three.

He was already at the door.

He had two minutes from when she turned toward the building. He picked up the maintenance clipboard and went out.

She was at the gate when he rounded the corner of the booth.

"Oh — you're back." He let the recognition register naturally. "From Traffic, right? Last week."

"That's right." She had a half-smile — not warm exactly, but not guarded. "Just passing through. Do you mind?"

"No, go ahead." He gestured at the gate. "I'm just doing the afternoon check."

She came through the gate and stood near the bulletin board. He stayed at the fence post and did the check — forty seconds, real — and then he had a decision to make about whether to go back inside or stay.

He stayed.

He wrote something on the clipboard that didn't need to be written and said: "Quiet today."

"Seems like it." She was looking at the bulletin board, but her attention wasn't on it. "It always this quiet?"

"Usually. That's why I'm here." He said it with the slight downward inflection of the F-rank register — not a lot happens here, which is fine by me. "Not much demand for a security guard if there's nothing to secure."

She looked at him then. The assessment in her gaze was subtle — not obvious, not aggressive, just present in the way a current is present in water that appears still on the surface.

"How long have you been here?" she said.

"Three years."

"Long time."

"It's a good building. Quiet residents." He paused, in the way someone pauses when they're about to say something mild and true. "The old woman on the first floor brings me food sometimes. That's worth staying for."

Dieu's expression shifted, slightly. Something in the corner of it — not warmth, but the recognition of something genuine.

"She seems like a character," Dieu said.

"She's got opinions about the district parking rules." He delivered it flat. "Strong ones."

That got a small response — not quite a laugh, but the shape of one.

"Sounds like my landlord," she said.

Three sentences of actual exchange. He could feel the conversation starting to have texture — two people who were both intelligent and both knew the other was intelligent and were each deciding how much to show of that. He kept his side two levels below what he was actually doing.

"So the sweep," he said, shifting to practical. "Still same timeline?"

"Roughly. We're doing preliminary passes before the main operation."

"Anything I should tell residents?"

"Nothing new from what we gave you before." She paused. "We've been seeing some unusual energy readings in this sector. It's probably nothing — interference from the construction equipment two blocks over. But we're taking another look."

He let that land. Nodded. "The construction on Fifth? They've been at it for months. Drives Mrs. Nam crazy."

"That's probably it." She said it easily. He noted the word probably.

He looked at his clipboard. "I should finish the check before it gets dark."

"Of course." She stepped back from the board. "Thanks for the chat."

"Sure. Number's on the sheet we gave you if you need anything."

She nodded. Started back toward the gate. He went to the next fence post and did not watch her leave until he was at a position where watching was natural. Then he watched her walk away and turn the corner and disappear.

He stood at the fence post for ten more seconds.

Then he went inside.

---

Mien was in the spare chair.

Not at the window anymore — she had moved back to her standard position, the Traffic seal mechanics document open in front of her. But she wasn't reading it. She was looking at the wall opposite with the focused quality of someone who was thinking rather than seeing.

He sat down.

The room held its silence for a moment.

"She's good," Mien said.

"Yes."

"She gave you information."

"Yes. She said the unusual readings were probably interference from the construction equipment."

"And you said—"

"I said the construction on Fifth had been going on for months and bothered Mrs. Nam."

Mien was quiet for a moment. "So you confirmed the construction existed. Which she already knew. And she gave you cover for why a reading was showing up here."

"Yes."

"Which she doesn't actually believe."

"No."

"But she wanted you to take the cover."

He looked at the desk. "She wanted to see how I responded to it."

Mien turned from the wall to look at him. Her expression was the assessment one — but slightly different, the way it had been when she had said he was reading Dieu. Not reading the situation. Reading him.

"You talked to her differently than you talk to people here," she said.

He looked at the door. "I played F-rank."

"I know. That's not what I mean." She paused. "You were more careful. But not careful the way you're careful with the residents — that's a different kind of careful. With her you were..." She stopped. Tried again. "You were paying attention to her the way you pay attention to things that can pay attention back."

He looked at her.

She looked at him with that expression — the one without a name, the one that had been present since the corridor and had been, in the two days since the window, acquiring something additional that he had been not-examining with the careful not-examination he applied to things that were happening in the part of himself that kept accurate accounts.

"She's a professional," he said. "She requires different attention."

"Yes." Mien held his gaze for a moment. "I just noticed."

He looked at the contingency plan.

"She's going to be a problem," he said.

"I know."

"Not just because of the scanner."

"I know." A pause. "Because she's the kind of person who figures things out by paying attention to people."

He nodded.

Mien looked at the seal mechanics document. Looked at the window. Looked back at him.

"For what it's worth," she said, "I don't think she has you yet."

He held her gaze for a moment.

"Not yet," he said.

---

The System updated at nine-fourteen that evening.

[Traffic internal communication intercepted — partial. Dieu report filed: C-7 complex, preliminary social reconnaissance complete. Notes: Security guard, F-rank, 3 years on site. Behavioral profile: low initiative, routine-oriented, not flagged for enhanced screening. Anomaly: unregistered family visitor, recent arrival. Visitor profile: inconclusive. Building ambient reading: persistent low-level signal, likely equipment interference. Recommendation: enhanced scanner deployment within 48 hours for definitive assessment. Status: pending approval.]

He read it three times.

Behavioral profile: low initiative, routine-oriented, not flagged for enhanced screening.

She had bought it.

Not entirely — the visitor profile was inconclusive, which was Dieu's way of flagging something she hadn't resolved — but the primary subject had been assessed and filed as not significant.

He looked at the line: unregistered family visitor, recent arrival. Visitor profile: inconclusive.

Mien was reading the contingency plan update he had printed. She looked up when he turned the screen toward her.

She read it.

"She's not sure about me," she said.

"No. But she's filed you as an anomaly rather than a target. That's different from suspicion."

"How long does that distinction hold?"

"Until the enhanced scanner goes in." He paused. "Forty-eight hours."

Mien set the pen down. "Thirty percent."

"By tomorrow evening. Yes."

She looked at the ambient reading: thirty-four point eight. Stable.

"Thirty percent," she said again. Not question, not doubt. Confirmation.

"Yes," he said.

She picked up the pen. Went back to the margin notes.

He worked until midnight. He rebuilt the cover story — more layered, more specific, built for Dieu's level of scrutiny rather than casual inquiry. The true things were the building material. The structure was constructed around them.

At two in the morning, he sat in the dark and thought about visitor profile: inconclusive, and what he had just spent two hours doing, and why.

The honest version: he had rebuilt the cover story not only because the operational necessity required it, though it did. He had rebuilt it because the open question in Dieu's report had a name in it. Not his name. Hers.

He had built it better because it was for her.

He sat with that for a long moment.

Then he went to sleep.

---

In the morning he printed the rebuilt cover story and put it on the desk.

Mien picked it up without being asked and read it while he made breakfast. When he set her tea down she said, without looking up: "This is different."

"Yes."

"More specific."

"Yes."

She kept reading. He ate.

"The detail about the bus route," she said. "From the district I'm supposedly from. I didn't know that."

"I researched it last night."

She looked at him then. The expression was the one from yesterday — the one that was observing him rather than the situation.

"You rebuilt the whole thing," she said.

"The original was built for casual inquiry. Dieu isn't casual inquiry."

"No." She looked back at the document. "There's a section here about things I'd notice. About the city versus where I'm supposedly from. Things I'd find different."

"Yes."

"You wrote about how the street food is different. The vendors here versus the outdoor markets in that district."

"Yes."

She was quiet for a moment. "You spent time on that detail."

"It's the kind of detail that reads as true. People who've actually traveled notice those things."

"I know why it's effective." She set the document down. "I just noticed that you spent time on it."

He looked at his tea.

The session brought her to thirty-two point one percent. Below the thirty percent target. The enhanced equipment Traffic used typically classified above thirty-five. Below thirty created significant margin.

"Thirty-two point one," he said.

"Is that enough?"

"It should be."

She sat in the spare chair. He made tea, the second cup. He set it in front of her.

They ran the cover story five times. By the fourth run, her answers had the quality that distinguished a real person from someone reciting prepared material — complete but not exhaustive, occasionally self-correcting in ways that sounded like memory rather than script.

"Better," he said.

"How much better."

"Dieu would have to go significantly harder to break it now."

Mien looked at him. "Would she?"

He thought about the report. Visitor profile: inconclusive.

"I don't know," he said. "That's the honest answer."

She nodded. The nod that filed things.

"Then we practice again tomorrow," she said.

"Yes."

"And the day after."

"Yes."

She went back to the seal mechanics document.

He went back to the contingency plan.

The afternoon continued. The number was thirty-two point one. The clock was running. The cover story was rebuilt.

He looked at the map on the windowsill, the marks in two different pencil weights.

He looked at the spare chair, currently occupied.

He looked at the jacket on the sofa arm.

Then Mien said, without looking up from her reading: "For tôi biết when you're done with the new section."

He paused.

Tôi. Not the register she had been using. A slight shift — subtle, the kind of thing that only registered if you were already paying attention to it.

He was already paying attention to it.

"I'll let you know," he said.

He went back to work.

The lamp made its circle.

Outside, forty-eight hours were already running.