The sun wouldn’t set for another fifteen minutes, so he wouldn’t be out for hours, but Droog had tried to bolt onto the hermit’s property again when I took her out after work, and I’d been paranoid he might appear ever since.

“It’s magnetism that makes a compass’s needle point to the North Pole,” Sofía explained. “Only, sometimes, when lightning strikes, it can magnetize the rocks or soil or metal it hits. If any of that light struck the debris, it might work the same way. But we’ll have to get pretty close to the wreckage before the compass’s magnet could respond. Otherwise it’ll just pick up the Earth’s magnetic field and point north.”

“What if it wasn’t the same thing as lightning?” I asked.

Sofia frowned. “Maybe it will have the same effect? Or maybe nothing.”

“Just keep your eyes open,” Arthur said impatiently. “Watch for burns, or anything suspicious, and we’ll find the wreckage, whether the compasses work or not.”

He pulled the Walmart bag off his handlebars and fished out a compass, handing it to Sofía, who seemed uncertain. “Did Nick . . . get these for us?”

“He’s trying to pull his weight in his own way,” Arthur said, as if we were some kind of military outfit. Sofía took the stolen compass between two fingers, like it was covered in toxic waste, and Arthur went on. “We’ll go the long way, through the woods behind the Jenkins House. That way we can make sure there’s no one around the power plant or the field before we spread out.”

Art handed a compass to Levi, then pulled one out for me. My chest tightened. My mouth went dry.

What if the needle starts to spin now?

What if I’m magnetized by the thing in me?

Black Mailbox Bill’s warnings sizzled through my mind. I reached out fast, bumping Arthur’s arm so hard the compass went flying.

“Jeez!” he yelped.

“Sorry!” I hopped off my bike and discreetly checked the compass before picking it up.

Thank God.

It wasn’t spinning. Whatever else that thing had done to me, apparently it hadn’t turned me into an outright magnet.

“Be more careful with any evidence you find,” Arthur said, and kicked off as I boarded my bike again.

The sun had set by the time we reached the back of the Jenkins House, but I left the headlight off as we edged around the siding.

Temporary floodlights had been erected in a rectangle around the substation’s fence, washing the deep blues and greens from the night. A truck was parked on the gravel road, but there was no one in the cab, and the same went for the scuffed yellow Bobcats in the field to the left of the substation.

“No people,” Sofía whispered. “But there might be security cameras.”

“Stick to the shadows,” Arthur commanded. “And if you find anything, don’t get too close until the rest of us can join you.” He stood on his pedals and cruised down the slight hill, cutting a wide arc around the illuminated portion of road.

“Where should we look first?” Levi asked.

“The point was to split up,” Sofía said, and took off in the opposite direction from Arthur.

“Looks like it’s just us. Team Franvi. LeFra?”

I was dreading going into the house alone, but I really didn’t need an audience for this. “I was going to look around inside,” I said. “You should check the woods behind the house.”

Levi huffed. “Bunch of lone wolves.” He rode into the patch of woods where I’d found the bullets, and I left my bike against the house and headed for the axed front door.

I glanced over my shoulder to be sure the others were out of sight, then took out my flashlight and bushwhacked the darkness back as I scoured the shaggy grass for my necklace.

The pendant was a real nautilus shell. Mark had carefully sawed it open to reveal the many chambers within, arranged in their delicate spiral. He’d coated the whole thing in resin to protect it, then drilled a hole for the chain.

It was the shell that had started his whole obsession. He’d found it on the beach, on a family vacation when I was ten, Arthur was eleven, and Mark was sixteen.

“Do you know why logarithmic spirals matter?” he’d asked us.

We didn’t even know what logarithmic spirals were.

“They’re everywhere,” Mark told us. “In pinecones and sunflower seedheads and hurricanes—even the way a hawk will approach its prey, if the prey’s running in a straight line. It’s a spiral where every turn gets bigger by the exact factor it takes to keep the spiral the same shape. It’s growing, fast, with each turn, but it’s still staying the same. Isn’t that amazing?”

“If by amazing you mean boring,” Arthur had said.

Mark had ignored the comment, or maybe he’d been so excited he didn’t notice the sand Arthur was flinging at him in an attempt to get him to play some rough-and-tumble game. Mom had looked up from the scientific journal she was reading and laughed. “How could the building blocks of all creation be boring to a child of mine, Arthur?”

Dad had ruffled Arthur’s sun-streaked hair. “Add enough math talk to anything, and you can take the joy out of it, right, Art?”

“Even the galaxy, the whole Milky Way is a logarithmic spiral,” Mark had forged on. “And there are always black holes in the middle of spiral galaxies, but there’s a huge city of them at the center of ours! Every one of those black holes came from a dying star—or a cluster of them. As the star loses fuel, it and its temperature change, its internal pressure can no longer resist the star’s own gravity. The whole star collapses, gets pressed into this tiny thing, smaller than an atom, but still with all the mass of the giant star. With all that gravitational force now fixed to this tiny point.”