Sam spun to look at her, but before he could ask what she was doing, he heard a set of answering claps from somewhere far away to the west. The same pattern of three claps in rapid succession.

He looked past her, west along the road, and saw a huge barn a quarter mile in that direction. Its long side was probably a hundred feet wide and forty feet tall. It was a giant, perfectly flat surface, facing the schoolhouse as directly as a movie screen faced an audience.

Sam offered a dry smile. “If you dragged me all the way out here to ask me where the echo comes from, you’re slacking in the riddle department.”

Dani returned the smile. “Yeah, yeah. Everyone knows where the echo comes from.”

“So what’s the riddle?”

For a moment she didn’t answer. She walked farther into the overgrown yard, until she was halfway between the road and the schoolhouse. Then she turned back to Sam, and raised her arms in a sweeping gesture that took in everything around her. Echo House and all of its surroundings.

“Lauren and I used to come out here all the time,” she said. “No reason. It was just a place to hang out. A place to ride our bikes to. We’d stay for an hour, sometimes longer. We’d probably been here half a dozen times before we finally noticed something about it. Something … weird.”

“Weird?” Sam said.

“Really weird.”

“What is it?”

“That’s the riddle. See if you can spot what’s weird.”

Sam frowned. “Lots of things about it are weird. No one cuts the grass. The door’s falling off. The roof’s made of stone.”

“Lauren and I didn’t need half a dozen visits to notice those things.”

“Well, is it something inside or outside?”

Dani shrugged, smiled, and mimed zipping her mouth shut and locking it.

Sam shook his head and turned his attention on the schoolhouse.

“What’s the penalty if I don’t figure it out?” he asked.

“I think you’ll get it. And I’ll go easy on the scoring. Lauren and I took forever to see it. But then again, we didn’t know we were looking for it.”

For the next hour Sam studied every detail of the place. He and Dani talked about random things—movies, books, Nintendo—but he didn’t ask for any more clues to the riddle. He also didn’t call out every little thing he saw that seemed potentially weird enough, hoping to hit on the answer. Better to play it cool until he was sure he had it right.