He scrutinized the outside of the structure first. He saw lots of things that drew his attention, but none of them seemed especially weird. There were two bricks missing, side by side on the back wall, about waist high. There was a bird’s nest tucked up under one of the eaves, dry and crumbling like it’d been there for years. There was an old lever-action water pump in the side yard, with OMAHA VALVE CO. imprinted on the handle, and spiderwebs strung from the spout.

After checking everything he could see outside, Sam went to the door. It opened without much effort, though it ground against its frame with a metal scream. He heard the sound ricochet off the distant barn even as he stepped into the schoolhouse.

For a few seconds, as his eyes adjusted, he worried about stepping on rotted floorboards and falling through to some kind of basement. Then the details resolved, and he saw that there was no basement at all. The floor was made of flagstones set in cement. In fact, he’d already seen the floor from outside, he realized. It extended right under the walls and beyond, by about six inches on all sides. That made it a very simple foundation: a broad stone platform slightly larger than the building that rested on it. None of which qualified as weird. Sam moved farther inside, and heard Dani enter behind him.

Seen from the interior, away from the glare of the summer afternoon, the schoolhouse was actually pretty bright. The windows were small by modern standards, but there was more than enough light to compensate.

Sam looked around. Here, again, lots of things caught his eye, but none of them struck him as unusual. He saw metal candleholders built into the walls every four feet. Most were empty, but melted stubs remained in a few of them. In the back left corner there was an iron potbelly stove. Its door was long gone, and its chamber was full of weeds and sticks where some animal had made a home, maybe over the winter. For a moment the stove itself seemed like a possible answer to the riddle: it had stood out here unattended for over half a century since the school shut down, and nobody had come along and stolen it. That was at least a little weird. Then Sam saw the reason: each of the stove’s legs flared out at the bottom, like the business end of a trombone, and the edges of each flare were trapped securely under the flagstone slabs of the floor. The stove had been set in place first, and then the floor had been laid down around it, permanently locking it in position. Clever idea. But not weird.