Sam began pulling out the few movers’ boxes he’d set in the closet the other day. Dani joined in, and within another minute they had the space cleared, the back wall exposed all the way to the floor.

“I’ve heard it a bunch of times,” Sam said, “starting the day we moved in. I thought it was some random noise the house made. Like the hot water heater or something.”

He stepped to the closet’s threshold and studied the back wall. It was painted flat white, and was featureless except for wire shelves at chest and head height. There was no way to access the space behind the wall without simply cutting into it. Sam leaned into the closet and looked up at its ceiling. There was a narrow hatch there, which led to the attic.

“We need something to stand on,” he said.

There was no ladder in the house, but the end table next to the couch was tall enough to do the trick. After sliding it into the closet and climbing onto it, Sam could reach the ceiling hatch easily. He shoved it up and off to the side, and a moment later he was sitting in the dim space of the attic, his feet hanging down through the opening. He reached back down and helped Dani up. She clambered into a seated position next to him.

It was easily ninety degrees up here, and thick with humidity, and though the attic was empty, it still managed to feel cramped. Shallow-angled roof beams made up its ceiling, and four-by-eight-foot chipboard sheets comprised the floor. The air was heavy with the smells of wood and dust and something like glue—probably roofing tar.

Sam studied the piece of chipboard beside the hatch, directly above the space behind the closet. At a glance, it looked no different than the rest of the sheets. Then he looked closer.

This board had no nails holding it down, like all the others did. It was just resting in place.

There was a gap at the near edge of the chipboard sheet: an inch of empty space between the board and the wooden frame that surrounded the hatchway. Sam got his fingers through the gap and took hold of the board, and found he could tilt it up easily. Dani got a grip on it, too, and together they shoved it aside.

The exposed rectangle where the board had lain was spanned by heavy structural beams. Sam realized he was looking at the living room ceiling from above. The spaces between the beams were filled with insulation—except one. The nearest one. In that space there was only darkness, leading down to a cavity behind the closet wall.

Dani leaned over it.

“Light switch,” she said. She reached down into the dark and flipped a switch that had been crudely wired into place near the top of the wall, and the hidden chamber was bathed in white fluorescent light.