“Will it hurt him?” I asked.

I surprised myself with the question, and Bentham, too.

“Does that matter?” he replied.

“I’d rather it didn’t. If we have a choice.”

“We don’t,” Bentham said, “but it won’t feel any pain. The chamber fills with anesthetic sleeping gas before anything else happens.”

“And then what?” I said.

He smiled and patted my arm. “It’s very technical. Suffice to say, your creature will leave the chamber alive, in more or less the condition he entered it. Now, if you would kindly have it step inside.”

I wasn’t sure I believed him, nor why it mattered to me. The hollows had put us through hell and seemed so lacking in feeling that inflicting pain on them should have been a pleasure. But it wasn’t. I didn’t want to kill the hollow any more than I wanted to kill a strange animal. In the course of leading this creature around by the nose, I had gotten close enough to understand that there was more than just void inside it. There was a tiny spark, a little marble of soul at the bottom of a deep pool. It wasn’t hollow—not really.

Come, I said to it, and the hollow, which had been lurking shyly in the corner, stepped around Bentham to stand before the booth.

Inside.

I felt it waver. It was healed now, and strong, and if my hold on it faltered for even a moment, I knew what it might do. But I was stronger, and a battle of wills between us would’ve been no contest. It wavered, I think, because I had.

I’m sorry, I said to it.

The hollow didn’t move; sorry was input it didn’t know what to do with. I just needed to say it.

Inside, I said again, and this time the hollow complied and stepped into the chamber. Since no one else would touch it, from that point Bentham told me what to do. Per his instructions, I pushed the hollow against the back wall and crossed the leather straps over its legs, arms, and chest, buckling them tight. They were clearly designed to restrain a human being, which raised questions to which I didn’t want the answers right now. All that mattered was moving forward with the plan.

I stepped out, feeling stifled and panicky from the few moments I’d spent inside.

“Close the door,” Bentham said.

When I hesitated the assistant moved to do it, but I blocked his way. “It’s my hollow,” I said. “I’ll do it.”

I planted my feet and grabbed the handle and then—though I tried not to—looked into the hollow’s face. Its great black eyes were wide and frightened, all out of proportion with its body, small and shriveled like a cluster of figs. It was still and would always be a disgusting creature, but it looked so pathetic that I felt unaccountably terrible, like I was about to put to sleep a dog who didn’t understand why it was being punished.

All hollowgast need to die, I told myself. I knew I was right, but it didn’t make me feel any better.

I pulled on the door and it screamed shut. Bentham’s assistant hooked a giant padlock through its handles, then went back to the machine’s controls and began twiddling dials.

“You did the right thing,” Emma whispered in my ear.

Gears began to turn, pistons to pump, the machine itself to thrum with a rhythm that shook the entire room. Bentham clapped his hands and grinned, happy as a schoolkid. Then from inside the chamber came a scream the likes of which I’d never heard.

“You said it wouldn’t hurt him!” I shouted at Bentham.

He turned to shout at his assistant. “The gas! You forgot the anesthesia!”

The assistant scrambled to pull another lever. There was a loud hiss of compressed air. A wisp of white smoke curled from a crack in the chamber door. The hollow’s screams gradually faded.

“There,” said Bentham. “Now it feels nothing.”

I wished for a moment that Bentham was in that chamber instead of my hollow.

Other pieces of the machine came alive. There was the sound of liquid sloshing through the pipes above our heads. Several small valves near the ceiling rang like bells. Black fluid began dripping down through the machine’s guts. It wasn’t oil, but something even darker and more pungent—the fluid that the hollowgast produced almost constantly, that wept from its eyes and dripped from its teeth. Its blood.

I’d seen enough and walked out of the room feeling sick to my stomach. Emma followed me.

“Are you okay?”

I couldn’t expect her to understand my reaction. I hardly understood it myself. “I’ll be fine,” I said. “This is the right thing.”

“It’s the only thing,” she said. “We’re so close.”

Bentham hobbled out of the room. “PT, upstairs!” he said, and he tipped himself into the bear’s waiting arms.

“Is it working now?” Emma said.

“We’re going to find out,” Bentham replied.

With my hollow restrained, sedated, and locked inside an iron chamber, there was little danger in leaving him behind—and yet I lingered by the door.

Sleep, I said. Sleep, and don’t wake up until this is over.

I followed the others out through the machine rooms and up several flights of stairs. We came to the long, carpeted hallway that was lined with exotically named rooms. The walls hummed with energy; the house seemed alive.

PT set Bentham on the carpet. “Moment of truth!” he said.

He marched to the nearest door and flung it open.

A humid breeze blew into the hall.