Sam noticed the echo of her voice changing as they descended. When they’d first entered the stairwell, the reverberations had all come from below. Now they seemed to be coming from high above. They must be getting near the bottom.

“By the end of that first month,” Dani said, “Lauren and I could see exactly how this town does that to people. How it trains them. It’s almost an automatic thing. It comes from every conversation. Every time someone tells you to keep quiet for your own good, every time they cut you off midsentence, and look around like they’re afraid someone overheard … every moment like that, you feel yourself getting a little more scared, too. Wanting to just keep your head down and not make trouble.”

They rounded one more landing, and Sam saw a final flight of steps, and at the bottom a concrete floor maybe fifteen by fifteen feet.

He saw the two doors, facing each other across the square space, one on the left wall and one on the right. The left door had the keypad. The other had nothing but a handle. They descended the last few steps and made their way to the right-side door.

“We almost gave in,” Dani said. “We really almost did.”

She looked up and met his eyes.

“Come on,” she said at last, and pulled the door open.

Sam followed her through. A second later he felt his thought process come to a dead stop.

Somewhere in the back of his mind, it occurred to him that people often used the word stunned to describe their feelings. If a baseball team came from behind to win in the ninth, or some celebrity couple split up, people said they were stunned by it. He himself had probably used the word lots of times. But now, standing in the space beyond the stairwell door, it was clear as pool water that he had never been truly stunned by anything.

Until now.

The chamber they’d entered had a ceiling as high up as that of the gymnasium in his school back in L.A. Sixty feet up, maybe. The width and length of the chamber, however, put the gymnasium to shame. He wasn’t even sure he could gauge the size of this space. It extended hundreds of feet in both directions, the vastness terminating at what looked like concrete walls, way out in the gloom where the flashlights could barely reach. Their two beams were grossly outmatched by the size of the place. They might as well have been penlights.

Sam moved his beam along the massive steel trusses that held up the ceiling, supported every fifty feet or so by upright columns. He saw complex triangular framing, like the supports of a railroad bridge. He tried to imagine the weight of soil pushing down on the ceiling from above—there were another sixty feet of dirt on top of this open space.