Attenuation

She told Dev on a Saturday, in his apartment, because she had decided that if she was going to do this at all, she needed to do it somewhere that wasn't the lab, somewhere that still belonged, at least nominally, to the version of her life that existed before the caterpillar cake.

He listened to all of it without interrupting, which she had forgotten he was capable of — during their relationship he had been a compulsive interrupter, a finisher of sentences, and the two years since had apparently taught him something about waiting that she found herself grateful for now, in a way that had nothing to do with the old feeling between them and everything to do with the simple mercy of being heard all the way to the end of a sentence before being told it was impossible.

When she finished, he was quiet for a long moment.

"Say the last part again," he said. "About the cake."

"A caterpillar cake. Six candles shaped like—"

"No, the part where you said it wasn't a metaphor."

"I don't think it was a metaphor," Mara said. "I think it was a memory. Someone's memory. Not mine."

Dev rubbed his face with both hands, a gesture she recognized from a hundred late nights in grad school, the specific exhaustion of a person trying to hold two incompatible facts in his head at the same time without either one breaking. "You're a scientist," he said. "You know what this sounds like."

"I know exactly what this sounds like. I've been documenting it like a case study specifically because I know what it sounds like, and specifically because the alternative — that I write nothing down and simply wait to find out whether I'm having a neurological crisis — is not an alternative I can live with."

"Okay." He nodded slowly. "Okay. Show me the logs."

They spent the rest of the weekend in his apartment with both laptops open, the raw architectural data from her deep scan spread across one screen and Dev's own diagnostic access — narrower than hers, but real — cross-referencing against MindBridge's anonymized data repository, the aggregate pool that clinical partners were permitted to query for population-level research, provided the queries stayed sufficiently abstract that no individual patient could be identified.

Mara did not stay abstract. She built the query with the precision of someone who had spent sixteen years learning exactly how to ask a database the specific question she needed answered without technically breaking the rule against asking it.

*Show me every Halo v3.1 unit exhibiting resonance index greater than 0.85, correlated against user-reported cognitive-professional classification, over the last eighteen months.*

The number that came back made Dev sit back from the screen entirely.

"Point three percent," he said.

"Of twelve million users."

"That's—"

"Thirty-six thousand people," Mara said. She had already done the arithmetic, three times, hoping each time for a different answer. "At minimum. That's an eighteen-month window on a device that's been in market for three years. If the effect has a lag, if it's cumulative, if it's still spreading —"

"It's not spreading like an infection, Mara, it's a design flaw responding to a resonance parameter—"

"I don't know what it is," she said, sharper than she meant to. "That's the entire point. Neither do you. Neither does Fenn, or Fenn knows and is lying, and either possibility is worse than the one before it."

They looked at the number together for a while. Thirty-six thousand people, at minimum, somewhere in the country, waking at four in the morning to hearts beating in intervals too precise for a human body, dreaming architecture they didn't have names for, tasting coffee they hadn't ordered and reaching, in memory, for birthday candles that belonged to somebody else's childhood.

"The pattern held," Dev said finally. "High plasticity. Creative and analytical professions. It's selecting for something."

"Or it's not selecting for anything. It's just resonating strongest with the substrates most receptive to resonance. The same way a tuning fork doesn't choose which glass to shatter. The glass with the matching frequency shatters because of what it already is, not because the fork wants it to."

"That's a very generous way to describe what might be happening to your brain."

"I'm not being generous," Mara said. "I'm trying to be accurate. There's a difference, and it matters, because if this thing has intentions, we're dealing with an adversary. If it doesn't — if it's just a physical process finding the path of least resistance through thirty-six thousand human nervous systems — then we're dealing with something else. Something that might not even know what it's doing to us."

Dev was quiet for a long moment, looking at her in a way that made her aware, suddenly, of how tired she must look, how long it had been since she'd slept a night that felt entirely like her own.

"Does that make it better or worse?" he asked. "That it might not know?"

She didn't have an answer for that. She still didn't have one three hours later, driving home through the fog, the city's diagram of lights smearing past her windshield, the warm place at the back of her neck present in her awareness in a way it had never been before the caterpillar cake, before the foundry smell, before she had learned the word for the specific ache of watching something end that you weren't ready to see end — a word that, she realized with a small cold lurch somewhere beneath her sternum, she had not thought about in nine days, and that had just now, unbidden, surfaced again, sitting in her mind with the same borrowed clarity as everything else that no longer felt entirely like it was hers to keep.