"There are nanoparticles in the stomach?" I said. "How did they get there? Did the rabbit eat them? Swallow them involuntarily?"

"I doubt it. I would assume they entered actively."

I frowned. "You mean they crawled down the-"

"Esophagus. Yes. At least, I think so."

"Why would they do that?"

"I don't know."

She never paused in her swift dissection. She took scissors and cut upward through the breastbone, then pushed the rib cage open with her fingers. "Hold here." I moved my hands to hold the ribs open as she had done. The edges of bone were sharp. With my other hand, I held the hind legs open. Mae worked between my hands.

"The lungs are bright pink and firm, normal appearance." She cut one lobe with the scalpel, then again, and again. Finally she exposed the bronchial tube, and cut it open. It was dark black on the inside.

"Bronchi show heavy infestation with nanoparticles consistent with inhalation of swarm elements," she said, dictating. "You getting this, Bobby?"

"Getting it all. Video resolution is good."

She continued to cut upward. "Following the bronchial tree toward the throat…" And she continued cutting, into the throat, and then from the nose back across the cheek, then opening the mouth… I had to turn away for a moment. But she continued calmly to dictate. "I am observing heavy infiltration of all the nasal passages and pharynx. This is suggestive of partial or full airway obstruction, which in turn may indicate the cause of death." I looked back. "What?"

The rabbit's head was hardly recognizable any longer, she had cut the jaw free and was now peering down the throat. "Have a look for yourself," she said, "there seems to be dense particles closing the pharynx, and a response that looks something like an allergic reaction or-" Then Ricky: "Say, are you guys going to stay out much longer?"

"As long as it takes," I said. I turned to Mae. "What kind of allergic reaction?"

"Well," she said, "you see this area of tissue, and how swollen it is, and you see how it's turned gray, which is suggestive-"

"You realize," Ricky said, "that you've been out there four minutes already."

"We're only out here because we can't bring the rabbit back," I said.

"That's right, you can't."

Mae was shaking her head as she listened to this. "Ricky, you're not helping here…"

Bobby said, "Don't shake your head, Mae. You're moving the camera back and forth."

"Sorry."

But I saw her raise her head, as if she was looking toward the horizon, and while she did so, she uncorked a test tube and slipped a slice of stomach lining into the glass. She put it in her pocket. Then looked back down. No one watching the video would have seen what she did. She said, "All right, we'll take blood samples now."

"Blood's all you're bringing in here, guys," Ricky said.

"Yes, Ricky. We know."

Mae reached for the syringe, stuck the needle into an artery, drew a blood sample, expelled it into a plastic tube, popped the needle off one-handed, put on another, and drew a second sample from a vein. Her pace never slowed.

I said, "I have the feeling you've done this before."

"This is nothing. In Sichuan, we were always working in heavy snowstorms, you can't see what you're doing, your hands are freezing, the animal's frozen solid, can't get a needle in…" She set the tubes of blood aside. "Now we will just take a few cultures, and we're done…" She flipped over her case, looked. "Oh, bad luck."

"What's that?" I said.

"The culture swabs aren't here."

"But you had them inside?"

"Yes, I'm sure of it."

I said, "Ricky, you see the swabs anywhere?"

"Yes. They're right here by the airlock."

"You want to bring them out to us?"

"Oh sure, guys." He laughed harshly. "No way I'm going out there in daylight. You want 'em, you come get 'em."

Mae said to me, "You want to go?"

"No," I said. I was already holding the animal open; my hands were in position. "I'll wait here. You go."

"Okay." She got to her feet. "Try and keep the flies off. We don't want any more contamination than necessary. I'll be back in a moment." She moved off at a light jog toward the door. I heard her footsteps fade, then the clang of the metal door shutting behind her. Then silence. Attracted by the slit-open carcass, the flies came back in force, buzzing around my head, trying to land on the exposed guts. I released the rabbit's hind legs and swatted the flies away with one hand. I kept myself busy with the flies, so I wouldn't think about the fact that I was alone out here.

I kept glancing off in the distance, but I never saw anything. I kept brushing away the flies, and occasionally my hand touched against the rabbit's fur, and that was when I noticed that beneath the fur, the skin was bright red.

Bright red-exactly like a bad sunburn. Just seeing it made me shiver.

I spoke into my headset. "Bobby?"

Crackle. "Yes, Jack."

"Can you see the rabbit?"

"Yes, Jack."

"You see the redness of the skin? Are you picking that up?"

"Uh, just a minute."

I heard a soft whirr by my temple. Bobby was controlling the camera remotely, zooming in. The whirring stopped.

I said, "Can you see this? Through my camera?"

There was no answer.

"Bobby?"

I heard murmurs, whispers. Or maybe it was static.

"Bobby, are you there?"

Silence. I heard breathing.

"Uh, Jack?" Now it was the voice of David Brooks. "You better go in."

"Mae hasn't come back yet. Where is she?"

"Mae's inside."

"Well, I have to wait, she's going to do cultures-"

"No. Come in now, Jack."

I let go of the rabbit, and got to my feet. I looked around, scanned the horizon. "I don't see anything."

"They're on the other side of the building, Jack."

His voice was calm, but I felt a chill. "They are?"

"Come inside now, Jack."

I bent over, picked up Mae's samples, her dissection kit lying beside the rabbit carcass. The black leather of the kit was hot from the sun.

"Jack?"

"Just a minute…"

"Jack. Stop fucking around."

I started toward the steel door. My feet crunching on the desert floor. I didn't see anything at all.

But I heard something.

It was a peculiar low, thrumming sound. At first I thought I was hearing machinery, but the sound rose and fell, pulsing like a heartbeat. Other beats were superimposed, along with some kind of hissing, creating a strange, unworldly quality-like nothing I'd ever heard. When I look back on it now, I think that more than anything else, it was the sound that made me afraid.

I walked faster. I said, "Where are they?"

"Coming."

"Where?"

"Jack? You better run."

"What?"

"Run."

I still couldn't see anything, but the sound was building in intensity. I broke into a jog. The frequency of the sound was so low, I felt it as a vibration in my body. But I could hear it, too. The thumping, irregular pulse.

"Run, Jack."

I thought, Fuck it.

And I ran. …

Swirling and glinting silver, the first swarm came around the corner of the building. The hissing vibration was coming from the cloud. Sliding along the side of the building, it moved toward me. It would reach the door long before I could.

I looked back to see a second swarm as it came around the far end of the building. It, too, moved toward me.

The headset crackled. I heard David Brooks: "Jack, you can't make it."

"I see that," I said. The first swarm had already reached the door, and was standing in front of it, blocking my way. I stopped, uncertain what to do. I saw a stick on the ground in front of me, a big one, four feet long. I picked it up, swung it in my hand. The swarm pulsed, but did not move from the door.

The second swarm was still coming toward me.