“We’re behind this room right here,” Vaill whispered. “It could be some sort of storage area for things brought up by the elevator. There are two other spaces adjacent to where we are. From that larger room, a doorway leads to what’s labeled “Great Room,” with windows opening onto the cliff. Then there’s a corridor off of the Great Room that connects with the rest of the castle. I think this bottleneck is where they’ll be waiting.”

Lou agreed.

“Two ways inside,” he said. “One from the stone house, maybe for a truck making large deliveries to the storage areas, and the other from the boathouse down below.”

“So how do we get into the supply rooms?” Vaill asked. “No doors.”

Lou stood in the center of the space and listened. Then he put his hands against the cold concrete of the one wall.

“I hear machinery,” he whispered.

“A humming. I hear it, too. Coming from behind here.”

“So there’s almost certainly got to be a way inside. Otherwise this space makes no sense. Maybe from farther down the elevator shaft?”

Vaill withdrew another small black box from his pack, about the size of the detonator, and connected to a pair of cushioned headphones to it. Coming off the other side of the case was a small microphone.

“The future is now,” he said. “You can hear through five feet of concrete with this baby. I almost didn’t bring it.” He placed the small, disc-like receiver against the wall and then motioned for Lou to come take the earphones. “I hear voices,” Vaill said, “and I’m almost certain one of them is Dr. Kazimi. I think there’s only one other, another male, but it’s hard to make out what he’s saying. Here, have a listen.”

Lou donned the headphones. The humming noise he heard was louder now, but did not drown out the voices. It took some time for Lou to attune his ears to the sounds behind the wall.

“What do you need now,” he heard an accented voice say.

“Bring over agar and pour into petri dishes five millimeters deep.”

There was no mistaking the dense, shorthand speech of the man giving orders.

Humphrey!

Vaill took the device and listened some more.

“It sounds like they’re alone, working,” he said, “but I can’t be sure.”

“We’ve got to find the way in.”

“It’s a risk.”

“You going chicken on me, Agent Vaill?”

Vaill was about to protest when the listening device slipped from his hand and slid underneath the railing, clattering nosily down the stairs to the elevator platform. The seconds that the echo persisted seemed like an hour.