“So it would take loads of power,” I mused. “So how are they powering it?”

“That’s the real question,” she said. “After all, the Sign they raised at the Aquarium suggests that they have an ample supply.”

I shook my head. “No,” I stated. “That was Hellfire.”

Luccio pursed her lips. “You seem fairly certain of that.”

“I seem completely certain of that,” I said. “It’s powerful as Hell, literally, but it isn’t stable. It fluctuates and stutters. That’s why they couldn’t keep the Sign up any longer than they did.”

“To imprison the Archive, they would need a steady, flawless supply,” Luccio said. “A supply that big would also be able to support a very complex veil—one that could shield them from any tracking spell. In fact, it’s the only way they could establish a veil that impenetrable.”

“Ley lines,” I breathed.

“Ley lines,” she said with satisfaction.

“I know of a couple around town, but I didn’t realize there were that many of the things,” I said.

“The Great Lakes region is rife with them,” Luccio said. “It’s an energy nexus.”

“So?” Molly asked. “What does that mean?”

“Well, it’s one reason why so much supernatural activity tends to happen in this area,” I said. “Three times as many ships and planes have vanished in Lake Michigan as in the Bermuda Triangle.”

“Wow,” Molly said. “Seriously?”

“Yeah.”

“Next summer I think I’ll stick to the pool.”

Luccio started tracing various lines on the map with a fingertip. “The colors denote what manner of energy seems to be most prevalent in the line. Defensive energy here. Disruptive force here, restorative lines here and here, and so on. The thickness of the line indicates its relative potency.”

“Right, right,” I said, growing excited. “So we’re looking for an energy source compatible with the use of a greater circle, and strong enough to keep a big one powered up and stable.”

“And there are four locations that I think are most likely,” Luccio said. She pointed up toward the north end of Lake Michigan. “North and South Manitou islands both have heavy concentrations of dark energy running through them.”

“There’s plenty of spook stories around them, too,” I said. “But that’s better than two hundred miles away. If I were Nicodemus, I wouldn’t want to risk moving her that far.”

“Agreed. A third runs directly beneath the Field Museum.” She glanced up at me and arched an eyebrow as her voice turned dry. “But I think you’re already familiar with that one.”

“I was going to put the dinosaur back,” I said. “But I was unconscious.”

“Which brings us to number four,” Luccio said. Her fingertip came to rest on a cluster of tiny islands out in the center of the lake, northeast of the city, and the heavy, dark purple line running through it. “Here.”

Molly leaned across me and frowned down at the map. “There aren’t any islands in that part of Lake Michigan. It’s all open water.”

“Listens-to-Wind gave this map to me, Miss Carpenter,” Luccio said seriously. “He’s spent several centuries living in this general region.”