The third worm was charging straight toward me. "Chtorrrr! Chtorrrrrrr!" I didn't even have time to stand. I just pointed the torch and fired.

When I finally let go of the trigger, there was nothing left of the worm but a snaky dark mass of writhing, burning, rubbery flesh. It smelled terrible.

And then Duke was there, standing over me, offering me a hand. I thanked him as I pulled myself to my feet. He glanced around at the three burning worms. "You want to remember you're a guest here and leave something for the rest of us?" And then he was away, pointing and directing the rest of his team to fan out.

I looked at the three worms myself. "Babies, huh?" And shook my head. I didn't know if I wanted to meet Mama or not. Larry's team was already moving to the far side of the dome. My team was moving into position, but uncertainly; several of them were staring at me and the still-burning carcasses. They looked stunned. I clicked on my microphone. "Goddammit! Move out! Haven't you ever seen a man burn a worm before?" I started striding toward the back of the but. "Burrell! Get your ass in gear!" I wondered how badly mine would hurt tomorrow from that hard landing. I wasn't going to worry about it now. I hit the breakaways on my chest, kicked out of the drop harness and kept going.

I planted myself directly in front of the back wall of the dome. I gave it a lot of room. I checked the charges on my tanks. Still half full. Good. More than enough.

I glanced around behind me. Amy Burrell, white as a sheet, was fifty feet away. She held her rifle in a death grip. But she was ready. I looked at the wall again. Nothing. I checked the rest of my team. They were ready too.

My mike was still on. I switched channels and said quietly, "Apple."

"Baker," said Larry.

"Charlie," said Duke. "Hold your positions."

I looked at the rear wall of the dome. It was blank and featureless.

"All right," I barked. "Bring me a freeze machine. On the double."

The freeze machine was a large plastic crate filled with styrofoam doodles. Inside the doodles were two tanks of liquid nitrogen and a spray nozzle. They'd been dropped after everyone else was down safely. We had two of them.

If we hadn't wakened the Chtorrans with our arrival, we would have used the liquid nitrogen instead of the torches. Gottlieb and Galindo wheeled up one of the kits. Riley and Jein were just unloading the other. They touched the release and the crate popped open with a thump.

"I'll take the kit. Michael, you cover me with the torch." Gottlieb grinned as I passed it over to him. He loved the excitement.

The nozzle for the freeze machine was lighter than the torch, and I didn't wear the tanks on my back. It was Galindo's job to move them-if we had to move. I wore a pair of insulated gloves so thick they could have been used in a boxing match. I closed the faceplate on my helmet again and I was ready.

The back wall of the dome remained unchanged.

Duke's voice whispered in my earphones. "You okay, McCarthy?"

"I'm fine. But when this is over, my ass is going to hurt."

"You did good."

"I know," I said. And then I added, "Thanks."

There was silence for a bit, so I asked, "What happened with the blimp?"

"I don't know. I didn't have time to ask. We came over the edge and the wind shifted. But Ginny did her job. Nobody hit the water."

"When we get back, I'm going to buy her flowers."

"Do that. Better yet, buy her a bottle. It looked like a quick save." He was silent a moment, then asked, "Jim, how long do you want to wait?"

"At least a half-hour. Remember what happened to that team in Idaho."

"Right." Duke said, "There was a lot in that report to worry about."

"You mean the tunnel they found?"

"Yeah. If the worms are changing their nesting behavior . . ." He didn't finish the sentence; he didn't need to. The job was already difficult enough.

I studied the wall some more. There was no evidence of a hidden exit.

"Do you want to send in the Robe?" asked Larry. The blimp had also dropped a meter-high mechanical walker-a more sophisticated version of Shlep, the Mobe, only it didn't have Shlep's good looks or personality.

"No," said Duke.

Larry argued for it half-heartedly for a few moments, then trailed off. Duke didn't reply. I couldn't see either of them. There was just me and the wall.

"Jim?"

"Yeah, Duke?"

"You want to switch positions?"

"Naw, I'm fine."

"You sure?"

"I'm sure."

"All right."

The wall was unchanged. Something very small and loud buzzed around me. A stingfly? It was too fast to see. I waved it away with one gloved hand.

"Burrell? Time check."

"Twelve minutes, thirty seconds."

"Thank you."

I could feel myself sweating. I was starting to feel clammy inside the insulated battle-suit. I wished the fourth goddamn worm would quit waiting and come on out already.

"Come on, worm! I've got a nice cold bath for you! Just the thing for a hot summer afternoon!"

There was silence. Something hooted.

I found myself growing drowsy. I shook myself back awake; I stamped my feet, jumping back and forth from leg to leg for a moment.

I squeezed the trigger, just a touch, and let loose a cold cloud of freezing steam. It put a chill into the summer air and a cold pain into the eyes. Water droplets crystalized and pattered on the ground. That would keep me awake for a bit.

We'd been freezing worms for a month now. It was still a new technique. I didn't like it. It was more dangerous. And you still needed a backup man standing by with a torch, just in case.

But Denver had this idea that if you could freeze a Chtorran, then you could map it internally, so we'd been freezing them and sending them to the photo-isotomography lab in San Jose. I'd seen the process once. It was impressive.

You take a frozen Chtorran, you put it up on a big frame and you point a camera at one end. Then you start taking thin slices off of it, taking a picture of the cross section after each slice. You do this with the entire worm. Then you give the pictures to the computer.

The computer gives you back a three-dimensional map of the internal structures of the Chtorran body. Using a joystick and a screen you can move around inside the map and examine specific organs and their relationships to each other. We still didn't know half of what we were looking at, but at least we had something to look at now.

The process had been successfully completed with four gastropedes of varying sizes. We didn't know why, but they seemed to be from four different species. Denver was going to keep freezing and mapping worms until the discrepancies were resolved.

"Duke," I said.

"Yeah?"

"Why do you think the fourth worm always waits so long to attack?"

"Beats the hell out of me."

"Yeah. Well, thanks anyway."

"No trouble at all, son. If you don't ask questions, how will you ever learn anything?"

The wall in front of me began to bulge.

I studied it offhandedly. Odd. I'd never seen a wall do that. It bulged a little more. Yes, the dome was definitely being pushed out of shape. I raised the nozzle and pointed it directly at the center of the bulge.

"Duke, I think we got something. Burrell, pay careful attention now. I'll show you how this is done."

The dome began to crack ominously. The crack suddenly stitched up from the ground and across and then down again, and then the outlined piece began to topple outward

"CHTORRRRRRR!! CHTORRRRRRRRR!!"

This worm was the largest of them all! Was there no limit to their growth? Or was this the adult form?

It came sliding toward me like a freight train. I pulled the trigger and screamed and released a cloud of icy steam and a deadly spray of freezing liquid nitrogen. It spread out in sheets, enveloping the Chtorran. For a moment, it was hidden by the clouds and spray, and then it came plunging through, its fur streaked with white and icicles.