"We weren't sure if it was an innate power or not, leaning yes; we have an alloy that blocks telepathy but I couldn't feel any on you."

"I don't think a telepathy blocking helmet is something I can wedge into my skillset."

"It originally came in the form of a dorky helmet."

"I like to think mine is snazzy."

"It's way cooler, at least."

"Thank you."

"It belonged to this guy who wanted to start a nuclear war."

"Gosh. Well, this variety of apocalypse leaves more salvage."

"Yeah. And it ends at the border, but Canada and Mexico have a shoot-on-sight policy now in case the next escalation happens when a Sentinel chases a mutant over the border."

"Really. Okay then. And they can't tell who's a mutant and who isn't?"

"At first the Sentinels just targeted the mutants. Then they targeted mutants and known mutant sympathizers. Then they targeted suspected mutant sympathizers. Then some moron put in an algorithm with which Sentinels could decide who was a potential mutant sympathizer, and the Sentinels decided 'literally everyone except the people who built and deployed us.' Then that safety went out the window. Right now they're constrained by their programming to operate only within the United States, but no one is sure how long that's going to last and no one wants to go the way the US did."

"And nobody can come in and deal with them? Are they in Hawaii and Alaska too? Puerto Rico?"

"We don't know, I can build a radio sometimes but we're lucky if we get anything, even if we're barely far enough from the border not to get shot at."

"Yeah, everything Rete's picking up is encrypted."

"We're pretty sure that's Sentinel chatter, they coordinate."

"Maybe I can jam it. The first thing I made was a radar screamer, this wouldn't be that different."

"That would probably help, they're more dangerous in groups by a wider margin than just multiplying by how many."

"Yeah, they coordinated like a flock of Rete bots."

They surface next to the extremely perforated hulk of an inactive Sentinel.

"Let me know when moving something would be helpful."

"Can you get its armor off? I have emergency tools but they're pretty low power."

"I'll try to do it with all the pressure sensors intact," she says, and the chassis slowly pries itself apart.

"Okay. Here goes. Feel free to talk to Rete while I'm in Tinker fugue." And she goes at the parts of the Sentinel.

"...So...what's up with Tinkers?" Emily asks Rete.

"Tinkers have powers that allow them to create products within their specialty that mundane engineering cannot replicate," says Rete. "Lorica's specialty is robotics, loosely understood, but our team in Brockton Bay also includes a Tinker whose specialty is drugs and one whose specialty is compact efficient design, and Lorica makes use of a sort of ceramic produced by a Tinker materials engineer."

"Do you know why mundane engineering can't replicate it?"