“We’ll be an example to the public one way or another. Do you understand what that means? It means if we aren’t an example of how to shun a Jewish friend, we’ll be an example of what happens to people who don’t. I don’t know how we survive if I lose this job, let alone if…”

“I wondered about the timing of this,” I whispered. “Mayim thought maybe Dietger was outside the window.”

“They repeated back to me what you and I said last night,” Jürgen said. “There’s no way Dietger would have heard us so clearly if he was outside. It was as though the Gestapo were in the room with us.”

“I checked the study this morning,” I said, shaking my head. “Surely if there was a microphone in there, we’d be able to see it?”

“Maybe not,” Jürgen said hesitantly. He glanced at me. “There was talk at Kummersdorf about a weapons designer who went rogue. They say he was caught because of a passive listening device in his office. The Gestapo were supposedly sitting in the next building listening to every word he said. I never took the rumors seriously until last night. Secret listening devices? So small that a person wouldn’t even notice them, so small that they can’t even be found? The very idea seems so fanciful. I figured the rumor was just more propaganda. It would suit the Gestapo for people to think they could hear us even in the privacy of our offices or our homes too.”

“But…there is no sign of a device in that room. Could they really have invented invisible microphones that don’t even need electricity? There must be another explanation.”

“If you told an electronics engineer that I have reasonably reliable rockets firing on a regular basis, he’d probably say that’s absurd. For all we know, someone else working for Army Ordnance has designed passive microphones that really could be hidden in plain sight. We have to act as if it’s true.”

“We have to assume they can hear everything we say? Everywhere we go?”

“It’s probably safe out here,” he whispered. “Maybe there are ways we can cover the sound of our whispers inside, but we’ll have to be careful. We’ll never know which rooms they are listening in on…” He motioned toward Adele’s building next door. “Or even which homes.”

“Dietger was there when you were taken last night,” I said, my throat tight. The existence of such a technology might explain his mystical ability to stick his nose in everyone’s business. I felt physically ill. “I tried to call Lydia after the Gestapo took you. I didn’t know what else to do. She didn’t answer, and this morning their housekeeper told me they unplugged their phones last night.”