Page 33 of Kavan

Sophie sinks down inside a Precursor cell with it cupped in both palms and goes white.

"It's an index," she says. "It's the addressing key. Kavan, every challenge sequence in this city, every waymark count, every arch — this thing answers all of them. It's a master key and it belongs in a slot at the seat itself."

"They cut it out and left it behind."

"They left it with the prisoners, under guard, four hundred meters from a route they'd already cleared." She looks up. "Because they were coming back for it. Kavan, we need to leave right now."

We nearly make it.

The rear element hits us two hundred meters into the withdrawal, eleven of them, disciplined, in a gallery where I have no depth to fight and eight people who can't run. I lose the crystal in the first fifteen seconds. It isn't dropped. It's taken, off Obuya, by a woman who knew exactly which of us was carrying it and went through two of my officers to reach him.

We get everybody out. Nobody dies. That's the entire good news.

Sophie sits against the gutter wall afterward with her hands over her face for three seconds, and then she takes them away and is working again.

"He can skip every gate," she says. "Everything I've spent ten days reading, he now doesn't need. He goes straight up the spine, straight through the challenge arches, straight to the outer gate."

"How long?"

"Nine hours. Ten."

"Then we take the trench and we don't stop."

I put the column together in the gutter mouth and I do the last piece of administration this expedition will ever need from me.

"Halloran, you're on Vesk's element. He'll tell you what to carry and when to put it down. Marchant, you own every gram of charge we have and nobody touches it without your say. Enwright, you have the relay; Neris can't run comms and the lattice both. Kolar, you're with the wounded and you'll take Auclair's instructions and you won't apologize for being slow."

Twenty-three people, three of them found alive in a hole in the ground, which is more than I expected to be saying at any point this fortnight.

"Sophie."

"I know."

"You don't."

"Then say it."

"He gets there first," I say. "Accept that now, so it doesn't cost you a second when it happens. Our job isn't arriving before him. Our job is you, at that console, alive, for eleven minutes."

She considers me for a moment.

"Nine," she says. "I've been practicing."

CHAPTER 21

SOPHIE

What Obuya saved matters more than the crystal, and I don't understand that until the eighth hour of the march.

He had four archive shards in his boot. Nobody searched a twenty-four-year-old geodesist's boot for eight days, and he carried them out of that cell and handed them to me in a gutter unprompted, and when I said thank you he said, "You'll do something with them," which is the nicest thing anyone has ever assumed about me.

They're substation records. Local, not central, which means nobody curated them and nobody edited them.

I read them walking. Zuri rigs the reader to a shoulder strap so I can work at a pace that keeps me in the column, and Kavan puts himself at my left and steers me around obstacles with two fingers at my elbow, and in eight hours I don't walk into a single wall, which is a record.

And what I find rearranges the whole civilization.

The standard model, the one I taught, the one I published, says the Precursors were expansionist. Two centuries of scholarship built on the fact that we keep finding their fortifications and never find their homes. Threshold is a battery. Perrin is a battery. Osiris is a battery the size of an island.