“I’m going to check in with Armin about his algorithm and see if we can make some predictions about possible ward locations. Unfortunately, that’s where we’re stuck, unless the CPD wants to send folks out to every possible location.”

“And have them literally digging in the dirt?” Roger asked. “Unlikely.”

“I don’t think we have to do that,” I said, looking over the map. The pattern appeared random, at least based on geography or ley line location. But that didn’t mean they weren’t ascertainable. “In fact, I bet Rosantine’s already done some of that for us.”

Theo narrowed his gaze. “What do you mean?”

“Rosantine said she could ‘tell’ where the wards were.”

Petra nodded. “I see where you’re going—maybe she can sense the voids, too. Maybe that’s how she figured out Cornerstones existed in the first place.”

Roger sat forward, linked his hands together, and there was eagerness in his face. “And has been working through the hot spots systematically, looking for an unguarded ward.”

Theo nodded. “So, if we can figure out the ones she’s already eliminated, we can mark them off our list.”

“She feeds off chaos,” Petra said. “So maybe we search news stories for the last few days that suggest the kind of chaos chain reactions she can trigger. If it’s near one of these thirty-four hot spots, we mark it off the list and don’t need to check there.”

Theo looked at me. “Because if she’d actually found a ward and Cornerstone, it would have signaled, and we’d already know about it.”

“Exactly,” Petra said.

“We need cops at the hot spots,” Roger said. “Not to look for the Cornerstones—but to look for her.”

* * *

Cousin Armin sent his algorithm, which was essentially based on the theory we’d worked out with sugar packets at the coffeehouse: Since the wards were triggered by proximity, perhaps the Guardians had divided Chicago into geographic regions, with a ward and Cornerstone for each region that triggered if Rose got close enough.

For example, the ghosts at South Gate would have been triggered to attack as long as Rose stepped within the ward’s perimeter. If she’d been a few miles away from South Gate, the ghosts might have appeared at a farmhouse or even in the middle of a field. Of course, she’d gone directly for South Gate, because that’s where the Cornerstone had been. We still didn’t know how many wards there were, but we were getting closer.

We worked for hours, checking headlines for chaos chains and adding them to the map if they matched a void. We eliminated five more that way, in addition to three that didn’t match the algorithm for likely ward spots.

I also learned there was a lot of deeply weird stuff going on in Chicago. I mean, as residents and Ombuds, we’d known there were things that went bump in the night, and that the city had systemic issues that drove crime and violence.

But when you started really looking for the chaos? Deeply weird stuff.