But one look at his face told me he wasn't. If anything, he appeared weaker.

"Shit, Charley, what am I going to do with you?"

He didn't answer.

"I can't carry you. And David didn't leave any keys in his car, so we're out of luck-" I stopped.

What if David were locked out of his car? He was an engineer, he thought of contingencies like that. Even if it was unlikely to happen, David would never be caught unprepared. He'd never be flagging down cars asking if they had a wire hanger he could borrow. No, no. David would have hidden a key. Probably in one of those magnetic key boxes. I started to lie down on my back to look underneath the car when it occurred to me that David would never get his clothes dirty just to retrieve a key. He'd hide it cleverly, but within easy reach. With that in mind, I ran my fingers along the inside of the front bumpers. Nothing. I went to the back bumper, did the same. Nothing. I felt under the running boards on both sides of the car. Nothing. No magnetic box, no key. I couldn't believe it, so I got down and looked under the car, to see if there was a brace or a strut I had somehow missed with my fingers. No, there wasn't. I felt no key.

I shook my head, puzzled. The hiding place needed to be steel for the magnetic box. And it needed to be protected from the elements. That was why almost everybody hid their keys inside the car bumpers.

David hadn't done that.

Where else could you hide a key?

I walked around the car again, looking at the smooth lines of the metal. I ran my fingers around the front grill opening, and under the back license plate indentation. No key.

I started to sweat. It wasn't only the tension: by now I could definitely feel the drop in the wind. I went back to Charley, who was still sitting on the sideboard.

"How you doing, Charley?"

He didn't answer, just gave a little shrug. I took his headset off, and put it on. I heard static, and voices talking softly. It sounded like Ricky and Bobby, and it sounded like an argument. I pulled the mouthpiece near my lips and said, "Guys? Speak to me."

A pause. Bobby, surprised: "Jack?"

"That's right…"

"Jack, you can't stay there. The wind's been falling steadily for the last few minutes. It's only ten knots now."

"Okay…"

"Jack, you've got to come back in."

"I can't just yet."

"Below seven knots, the swarms can move."

"Okay…"

Ricky: "What do you mean, okay? Jesus, Jack, are you coming in or not?"

"I can't carry Charley."

"You knew that when you went out."

"Uh-huh."

"Jack. What the hell are you doing?"

I heard the whirr of the video monitor in the corner of the shed. I looked over the roof of the car and saw the lens rotate as they zoomed in on me. The Toyota was such a big car, it almost blocked my view of the camera. And the ski rack on top made it even higher. I vaguely wondered why David had a ski rack, because he didn't ski; he always hated cold. The rack must have come with the car as standard equipment andI swore. It was so obvious.

There was only one place I hadn't checked. I jumped up on the running board and looked at the roof of the car. I ran my fingers over the ski rack, and along the parallel tracks bolted to the roof. My fingers touched black tape against the black rack. I pulled the tape away, and saw a silver key.

"Jack? Nine knots."

"Okay."

I dropped back down to the ground, and climbed in the driver's seat. I put the key in the lock box and twisted it. The box opened. Inside I found a small yellow key. "Jack? What're you doing?"

I hurried around to the back of the car. I fitted the yellow key in the ignition. I straddled the bike and started it up. The motor rumbled loudly under the corrugated shed.

"Jack?"

I walked the bike around the side of the car to where Charley was sitting. That was going to be the tricky part. The bike didn't have a kickstand; I moved as close to Charley as I could and then tried to support him enough that he could climb onto the backseat while I still sat on the bike and kept it upright. Fortunately, he seemed to understand what I was doing; I got him in place and told him to hold on to me.

Bobby Lembeck: "Jack? They're here."

"Where?"

"South side. Coming toward you."

"Okay."

I gunned the motor, and pulled the passenger door shut. And I stayed exactly where I was.

"Jack?"

Ricky: "What's the matter with him? He knows what the danger is."

Bobby: "I know."

"He's just sitting there."

Charley had his hands around my waist. His head was on my shoulder. I could hear his raspy breathing. I said, "Hold tight, Charley." He nodded.

Ricky: "Jack? What're you doing?"

Then at my ear, in a voice just above a whisper, Charley said, "Fucking idiot."

"Yes." I nodded. I waited. I could see the swarms now, coming around the building. This time there were nine swarms, and they headed straight for me in a V formation. Their own flocking behavior.

Nine swarms, I thought. Soon there would be thirty swarms, and then two hundred…

Bobby: "Jack, do you see them?"

"I see them." Of course I saw them.

And of course they were different from before. They were denser now, the columns thicker and more substantial. Those swarms didn't weigh three pounds anymore. I sensed they were closer to ten or twenty pounds. Maybe even more than that. Maybe thirty pounds. They would have real weight now, and real substance.

I waited. I stayed where I was. Some detached part of my brain was wondering what the formation would do when it reached me. Would they circle me? Would some of the swarms hang back and wait? What did they make of the noisy bike?

Nothing-they came right for me, flattening the V into a line, then into a kind of inverted V. I could hear the deep vibrating hum. With so many swarms it was much louder. The swirling columns were twenty yards away from me, then ten. Were they able to move faster now, or was it my imagination? I waited until they were almost upon me before I twisted the throttle and raced forward. I passed straight through the lead swarm, into the blackness and out again, and then I was gunning for the power station door, bouncing over the desert, not daring to look back over my shoulder. It was a wild ride, and it only lasted a few seconds. As we reached the power station, I dropped the bike, put my shoulder under Charley's arm, and staggered the final step or two to the door.

The swarms were still fifty yards away from the door when I managed to turn the knob, pull, get one foot in the crack, and kick the door open the rest of the way. When I did that I lost my balance, and Charley and I more or less fell through the door onto the concrete. The door came swinging shut, and whanged into our legs, which hung outside. I felt a sharp pain in my ankles-but worse, the door was still open, kept ajar by our legs. Through the opening I could see the swarms approaching.

I scrambled to my feet and dragged Charley's inert body into the room. The door shut, but I knew it was a fire door, and it wasn't airtight. Nanoparticles could come right in. I had to get both of us into the airlock. We wouldn't be safe until the first set of glass doors had hissed shut. Grunting and sweating, I hauled Charley into the airlock. I got him into a sitting position, propped up against the side blowers. That cleared his feet of the glass doors. And because only one person could be in the airlock at a time, I stepped back outside. And I waited for the doors to close.

But they didn't close.

I looked on the side wall for some sort of button, but I didn't see anything. The lights were on inside the airlock, so it was getting power. But the doors didn't close. And I knew the swarms were fast approaching.

Bobby Lembeck and Mae came running into the far room. I saw them through the second set of glass doors. They were waving their arms, making big gestures, apparently indicating for me to come back into the airlock. But that didn't make sense. Into my headset, I said, "I thought you had to go one at a time."