〃No 。。。〃
She whispered； 〃You'll get us all killed。〃
He whispered； 〃I promise。〃
She shook her head； pointed to the ground。 Sit。
Finally； Bobby sat down。
Mae looked at me。 I nodded。 We set out again。 By now we were twenty feet from the mound itself。 The smell was almost overpowering。 My stomach churned； I was afraid I might be sick。 And this close； we began to hear the deep thrumming sound。 More than anything it was that sound that made me want to run away。 But Mae kept going。
We crouched down as we climbed the mound； and then lay flat along the rim。 I could see Mae's face in the green glow ing from inside。 For some reason the stench didn't bother me anymore。 Probably because I was too frightened。
Mae reached into the side pouch of her pack； and withdrew a small thumb…sized camera on a thin telescoping stick。 She brought out a tiny LCD screen and set it on the ground between us。 Then she slid the stick over the rim。
On the screen； we saw a green interior of smooth undulating walls。 Nothing seemed to be moving。 She turned the camera this way and that。 All we saw were green walls。 There was no sign of Rosie。
Mae looked at me； pointed to her eyes。 Want to take a look now？
I nodded。
We inched forward slowly； until we could look over the rim。
It wasn't what I expected at all。
The mound simply narrowed an existing opening that was huge…twenty feet wide or more； revealing a rock slide that sloped downward from the rim and ended at a gaping hole in the rock to our right。 The green light was ing from somewhere inside this gaping hole。 What I was seeing was the entrance to a very large cave。 From our position on the rim； we couldn't see into the cave itself； but the thrumming sound suggested activity within。 Mae opened the telescoping stick to its full length； and gently lowered the camera into the hole。 Soon we could see farther into the cave。 It was undoubtedly natural； and large： perhaps eight feet high； ten feet wide。 The rock walls were pale white； and appeared to be covered with the milky substance we'd seen on Rosie。
And Rosie's body was only a short distance inside。 We could see her hand sticking out around a bend in the rock wall。 But we could see nothing beyond the bend。 Mae signaled me： want to go down？
I nodded slowly。 I didn't like how this felt； I didn't like that I had no idea what was beyond the bend。 But we really had no choice。
She pointed back toward Bobby。 Get him？
I shook my head； no。 He wouldn't help us here。
She nodded； and started very slowly to slide out of her backpack； making no sound at all； when she suddenly froze。 Literally froze： she didn't move a muscle。 I looked at the screen。 And I froze； too。
A figure had walked from behind the bend； and now stood alertly at the entrance of the cave； looking around。
It was Ricky。
* * *
He was behaving as if he had heard a sound； or had been alerted for some other reason。 The video camera still dangled down the rim of the mound。 It was pretty small； I didn't know if he would see it。
I watched the screen tensely。
The camera didn't have good resolution and the screen was the size of my palm； but it was still clear that the figure was Ricky。 I didn't understand what he was doing here…or even how he had gotten here。 Then another man came around the bend。
He was also Ricky。
I glanced at Mae； but she remained utterly still； a statue。 Only her eyes moved。 I squinted at the screen。 Within the limits of video resolution； the two figures appeared to be identical in every respect。 Same clothes； same movements； same gestures and shrugs。 I couldn't see the faces well； but I had the impression they were more detailed than before。 They didn't seem to notice the camera。
They looked up at the sky； and then at the rock slide for a while； and then they turned their backs on us； and returned to the interior of the cave。
Still Mae did not move。 She had been motionless for almost a minute already and in that time she hadn't even blinked。 Now the men were gone； and…
Another figure came around the corner。 It was David Brooks。 He moved awkwardly； stiffly at first； but he quickly became more fluid。 I had the feeling I was watching a puppeteer perfect his moves； animating the figure in a more lifelike way。 Then David became Ricky。 And then David again。 And the David figure turned and went away。
Still Mae waited。 She waited fully two more minutes； and then finally withdrew the camera。 She jerked her thumb； indicating we should go back。 Together； we crept away from the rim； back down the mound； and moved away silently into the desert night。 We gathered a hundred yards to the west； near our vehicles。 Mae was rummaging in her backpack； she pulled out a clipboard with a felt marker。 She flicked on her penlight and began to draw。
〃This is what you're up against；〃 she said。 〃The cave has an opening like this； which you saw。 Past the bend； there's a big hole in the floor； and the cave spirals downward for maybe a hundred yards。 That brings you into one large chamber that is maybe a hundred feet high； and a couple of hundred feet wide。 Single big room； that's all。 There are no passages leading off； at least none that I saw。〃
〃That you saw？〃
〃I've been in there；〃 she said； nodding。
〃When？〃
〃A couple of weeks ago。 Back when we first started looking for the swarm's hiding place。 I found that cave and went in there in day…light。 I didn't find any indication of a swarm then。〃 She explained that the cave was filled with bats； the whole ceiling covered with them； packed together in a pink squirming mass； all the way out to the entrance。 〃Ugh；〃 Bobby said。 〃I hate bats。〃
〃I didn't see any bats there tonight。〃
〃You think they've been driven away？〃
〃Eaten； probably。〃
〃Jesus； guys；〃 Bobby said； shaking his head。 〃I'm just a programmer。 I don't think I can do this。 I don't think I can go in there。〃
Mae ignored him。 She said to me； 〃If we go in；〃 she said； 〃we'll have to set off thermite； and keep doing it all the way down to the chamber。 I'm not sure we have enough thermite to do that。〃
〃Maybe not；〃 I said。 I had a different concern。 〃We're wasting our time unless we destroy all the swarms； and all the assemblers that are making them。 Right？〃 They both nodded。
〃I'm not sure that'll be possible；〃 I said。 〃I thought the swarms would be powered down at night。 I thought we could destroy them on the ground。 But they're not powered down…at least not all of them。 And if just one of them gets past us； if it escapes from the cave 。。。〃 I shrugged。 〃Then this has all been a waste of time。〃
〃Right；〃 Bobby said； nodding。 〃That's right。 It'd be a waste of time。〃
Mae said； 〃We need some way to trap them in the cave。〃
〃There isn't any way；〃 Bobby said。 〃I mean； they can just fly out； whenever they want。〃 Mae said； 〃There might be a way。〃 She started rummaging in her backpack again； looking for something。 〃Meanwhile； the three of us better spread out。〃
〃Why？〃 Bobby said； alarmed。
〃Just do it；〃 Mae said。 〃Now get moving。〃
I tightened my backpack； and adjusted the straps so it wouldn't rattle。 I locked the night…vision goggles up on my forehead； and I started forward。 I had gotten about halfway to the mound when I saw a dark figure climb out into the night。
I dropped down as quietly as I could。 I was in a thick patch of sagebrush three feet high； so I was reasonably well concealed。 I looked over my shoulder； but I didn't see either Mae or Bobby； they'd dropped to the ground； too。 I didn't know if they'd separated yet。 Cautiously； I pushed aside a plant in front of me； and looked toward the mound。 The legs of the figure were silhouetted against the faint green glow。 The upper body was black against the night stars。 I flipped down the goggles； and waited a moment while they flared blue； and then saw the image resolve。
This time it was Rosie。 Walking around in the night； looking in all directions； her body vigilant and alert。 Except that she didn't move like Rosie； she moved more like a man。 Then after a moment； the silhouette changed into Ricky。 And it moved like Ricky。 The figure crouched down； and appeared to be looking over the tops of the sage。 I wondered what had brought it out of the mound。 I didn't have to wait long to find out。 Behind the figure； a white light appeared on the western horizon。 It grew rapidly in brilliance； and soon I heard the thumping of helicopter blades。 That would be Julia ing from the Valley； I thought。 I wondered what was so urgent that she had had to leave the hospital against orders； and fly out here in the middle of the night。
As the helicopter approached； it switched on its searchlight。 I watched the circle of blue…white light as it rippled over the ground toward us。 The Ricky figure watched； too； then slid down out of sight。
And then the helicopter roared over me； blinding me for a moment in the halogen light。 Almost immediately it banked sharply； and circled back。
What the hell was going on？
The helicopter made a slow arc； passing over the mound but not stopping； then ing to a stop right above where I was hiding。 I was caught in the blue glow。 I rolled onto my back and waved to the helicopter； pointing repeatedly toward the lab。 I mouthed 〃Go！〃 and point