O'Bannon was pulling on his left sock when his communication screen chimed softly, indicating a routine transmission.

It's starting already, O'Bannon thought. He reached over and tapped the key.When the image cleared, he said, very simply, "O'Bannon."

The face in the screen was that of an anxious young man. He was wearing field greens, a single bar, and a worried look. "Sir, "he said nervously.

"Lieutenant Crocker reporting."

There was a pause.

O'Bannon rubbed his hand across his forehead. "Well, then, Crocker," he said.

"Report."

"Yes, sir," Crocker said. "The intruder we logged yesterday morning still hasn't turned up. I think they've gone to ground someplace inside the reservation."

O'Bannon grimaced. "Well, then, they'd be sitting still, wouldn't they? If you 're on the move and they 're sitting still, it shouldn't be too hard to spot them, should it, Lieutenant?"

Lieutenant Crocker looked uncomfortable. "No, sir-no, sir; it shouldn't. I'm certain we'll turn them up. In any case, I've taken steps to make sure they don't get out of the area."

"I think that's an excellent approach, Crocker," O'Bannon said, with just the right tone of cynicism in his voice, "because if they do, I think we can find you a somewhat less sensitive job-on Nifflheim, or, perhaps, Yggsdrasil."

The muscles around Crocker's eyes were beginning to tighten. "I understand, Colonel," he said.

"Have you run an inbound spiral search?" O'Bannon asked.

"Uh-no, sir," Crocker said. "We've been doing standard grid."

O 'Bannon softened his expression. Already scared the kid to death, he thought. Time now to prop him up a bit. "Try running an inbound spiral. Five cars. Slideback formation. That should flush 'em if they're down in the brush someplace."

"Yes, sir. Thank you, sir," Crocker said.

"Okay, son," O'Bannon replied. "Report back before evening chow."

Jack Holloway and Gerd van Riebeek missed breakfast by a mile, but they arrived at Fuzzy Valley in time for the mid-morning coffee-break.

Sergeant Beltran motioned them aside. "You guys don't look like you ate yet today," he said. "Huh?"

They both shook their heads.

Beltran nodded in approval of his own sagacity. "Come on over to the kitchen scow. I'll fix you something up. You can't get by till lunch on coffee and pastry."

When they emerged from the kitchen scow, well-fed and still marveling at the meal which Beltran had whipped up on the spur of the moment-using odds and ends-an enormous closed cargo scow was just settling out of the sky. Its landing point was midway between the excavated wreck and the rockslide over the cave-mouth.Phil Helton was on the ground, talking the lander chief down to the right spot. O'Bannon, Stag well, and Casagra were off to one side, observing the operation.

"Come on, Gerd," Jack said. "Let's see what this is all about."

By the time they had walked to the site the scow had settled to the ground and lurched off contragravity.

After greetings had been exchanged, the flight crew had already secured the scow, the equipment crew had grounded the hatch-ramp, and a man wearing field greens and an orange cap was crunching across the ground toward them.

As the man drew closer, Holloway could see a black stencil on his left shirt pocket; an engineer's hammer, framed by the inverted " V " of a mason's square at the bottom and a spread divider compass at the top. "TFN" was stenciled below the design.

The man stopped, saluted the officers, and said, "Master Chief Construction Mate Lyman Byers reporting, sir. The difficult we do immediately; the impossible may take a whole shift."

O'Bannon returned the salute and looked slightly bilious. These guys from the construction battalion even have their own compliments on the load-list, he thought. He inclined his head toward Helton.

Chief Byers' face brightened as he ambled his lanky frame over to where Helton was standing with Jack and Gerd. "Whatcha" need, Gunnie? Gotta bore a big hole in something, huh?"

Gear was already coming out of the scow, to where the equipment crew was laying it out in precise rows on the ground.

Helton outlined his requirements as Byers listened attentively-with a concentration that was far different from his previous country-boy attitude.

"Take your own soundings," Helton said. "I want the shortest, straightest tunnel you can manage, but I want you to pull out when the headwall is about six inches short of breaking into the cavern. Can you cut it that fine?"

"No problem, Gunnie," Byers said seriously. "If the inside face of the rockfall was perfectly vertical, my operator could cut it fine enough to leave you a windowpane, if'n you wanted one."

Helton smiled. "Okay, get to it, then." By now the terrene itself had come out of the scow, on its own contragravity skid. It had the look of a short, fat torpedo with a snubbed-off nose. Directly behind it came the control cabin, a collapsium-hulled affair of smaller diameter than the terrene head. It housed all the sensors, controls, and pickups, as well as the operator. To the rear of it, it carried a collapsium counterweight, so that when the entire affair was on contragravity and working, the weight of the terrene to the front was balanced to level by the counterweight at the rear. As Byers loped off across the dry soil, his crew was already swarming over the equipment at the complicated task of mating the terrene with its control cabin.

"Your men are pretty flamboyant-with those blinding orange caps, aren't they?"

Gerd asked of no one in particular.

"Oh, there's a reason for it," Helton said. "That's a damned dangerous pieceof gear, especially when it's hot. They wear those gaudy caps so they can tell the players from the spectators. Anyone not wearing a loud orange cap gets within a hundred meters of that thing, the crew chief goes out and runs him off, be he captain, corporal, or general."

Holloway's itch of curiosity was getting the best of him. "Y'know, Phil, I've heard about those things, but I've never really seen one."

"That's not surprising," Helton said. "There are only six of them in the entire Federation Navy."

"Well, how does the damned thing work, is what I want to know," Holloway said.

"All I've ever heard is that it bores holes in solid rock-which makes no sense to me of itself." "In a nutshell," Helton continued, "there's a nuclear reactor inside the terrene itself. There are little bitty ones in the twenty centimeter models they use to bore drainage lines and air vents. There's a one-meter model. It makes a tube big enough for a man to crawl around in and string commo lines and fiber optic bundles along the walls. Then, there's this monster; two-meter tube. Makes nifty lift shafts and lateral drive tunnels to connect up underground complexes on places like Xerxes, where no-one can live on the surface."

"But how does it work?" Holloway insisted.

"I'm getting to that part," Helton said. "As the reactor heats up, a series of heat baffles raises the temperature of the outer skin until it's hot enough to vaporize rock-hotter for granite than for sandstone, for example. As the terrene proceeds through the rock, controlled by the operator in the collapsium cabin-who has to be a pretty brave guy, by the way-it also melts the rock around the periphery of the tunnel to a depth of several centimeters.

So, you see, it cases the tube as it goes, in a kind of crackle-finish glass-sometimes in very pretty colors, too."

"Hmmmm," Holloway said. "I see. What's the skin made of? Can't be collapsium.

Collapsium's a lousy heat conductor. Whatever it is, it must be wild stuff to take those temperatures."

"The answer to that is such a complicated secret that even I don't know it, "Helton said. He laughed. "And even if I did, I probably couldn't explain it.

In any case, it must cost like crazy to build the things. Otherwise we'd have more of them."

"How do they operate the little ones?" Gerd asked. "They'd be too small to have a control cabin with a man in it."

"Remotely," Helton said. "The control signals are input through a cable bundle that the terrene drags down the hole behind it. The operator works from a stationary console. But, the M-79 is so big and has so much mass that it has to be run with a tighter set of reins."

Mr. Throckmorton inhaled deeply before delivering the last point of Colonial case law noted in his brief. "The point, your Honor, is even more clearly stated in the case of The People of Yggsdrasil Colony versus The Federation Resident-General, The Chartered Yggsdrasil Company, et al.

As Throckmorton droned on, Attorney General Gus Brannhard was the picture of serenity on the outside, eyes half closed, not a muscle of his huge frame moving. Inside, though, he was dancing with glee as he awaited the conclusion of Mr. Throckmorton's precedents in this absurd matter of The Federated Sunstone Co-operative versus The Colonial Government of Zarathustra-so hecould rip the fool's shoddy case to pieces. Hugo Ingermann hadn't chosen very well. Now that he was barred from practicing law before Zarathustran courts, he had chosen The Honorable Eustis Throckmorton as his own personal shyster.

Perhaps Mr. Throckmorton had come cheaply. Ingermann's penchant as a centisol-pincher was well known.

Throckmorton finally wound down and finished his argument.

Justice Pendarvis nodded toward him, then turned his gaze toward Brannhard.

"How say you, Mr. Attorney General?" he asked.

Brannhard cleared his throat with a rumble."I say that Mr. Throckmorton's case is no case at all, and, in any event, cannot at present be heard by this court."

"And why is that, Mr. Brannhard?" Justice Pendarvis asked, although he knew the answer as well as Gus did.

' "The element of conspiracy has been cited in the plantiff's causes of action. It is a widely known point in Colonial Law that a colonial government-or any of its agencies-cannot be made the defendant in any complaint which cites conspiracy among the causes of action-uh-without the specific permission of that government for the plaintiff to pursue his case."

"Are you suggesting, then, Mr. Brannhard," Justice Pendarvis said, "that Mr.

Throckmorton's case cannot be tried in this court?"

"Not at all, your Honor," Gus replied. "Merely that it cannot be tried as the issues are presently framed unless Mr. Throckmorton petition the Colonial Government and obtain its permission for trial. I, for one, would not be friendly to such a petition, having the acquaintance that I do with Mr.

Throckmorton's employer."

Throckmorton's eyes were getting wider and wider.

"Object!" Throckmorton said hastily. "The present Colonial Government of Zarathustra is not one duly elected under the Federation Constitution. It is merely a fiat government, set up by Commodore Napier to govern pro tempore during the period between those decisions which bear your Honor's name and such time as proper elections can be held."

Justice Pendarvis leaned forward on his elbows. "Overruled, Mr. Throckmorton,"

he said quietly. "An appointed colonial government has all the force of authority as an elected one, save on one point. It cannot levy taxes."

"I-I forgot," Throckmorton said.

Brannhard fluffed his gray-brown beard. "I suggest," he said to no one in particular, "that Mr. Throckmorton was hoping that the Court had forgotten."

"There is an alternative, Mr. Throckmorton," Justice Pendarvis said.

Throckmorton's face took on a glow of anticipation. Perhaps there was a way to salvage this mess, after all.

"You may take your case to a Terran Federation Supreme Court on the home planet. They, having superior jurisdiction over this Colonial Supreme Court, will be pleased to hear your case, although I might suggest that the calling of witnesses might occupy a few years-considering travel times involved-and amount to no small expense to your client."Throckmorton's face fell.

Justice Pendarvis rapped his gavel lightly. "This case to be continued for a period of thirty days, in order to allow Mr. Throckmorton to prepare the petition in question. If such petition has not been secured by then, the case will be removed from the docket.

"Next case, please," Pendarvis said to the crier, as Throckmorton gathered up his brief and slunk out of the courtroom.

Great, noxious clouds of vapor and steam poured out of the tunnel as the terrene bored steadily into the rockfall. The remainder of the crew had cordoned off an area several hundred meters on a side with orange engineer's tape. Part of the men patrolled the perimeter, more for something to do than anything else. The rest, wearing breathing gear, were jockeying huge air-changers, each on its own contragravity sled, and blowing the fumes away with the prevailing breeze. Periodically, Byers, who was standing with his hands on his hips, talking to the operator over a commo attached to his earphones, would motion for the two work parties to switch off on their respective chores.

"That's very eerie," Hollo way said, as he stood and watched with Gerd and Phil. "I thought it would make more noise."

Helton shrugged. "Mighty engines must not always make a mighty noise. In this case, just the hiss of vaporizing stone and the noise of some of the glassed-up wall fracturing." He smiled. "You know what we call the three sizes of these things?"

Jack and Gerd both shook their heads.

"The little one," Helton said, "we call 'snap.' It doesn't make any more noise than a teakettle. The mid-size one we call 'crackle,' because it seems to cause more fracturing of the tunnel lining. Now, what do you suppose we call this one, the grandpappy of them all?"

Jack hesitated for a moment. "Pop?" he said tentatively.

Helton winked and made a single, decisive gesture with his index finger. "You got it," he said.

The vapor clouds began to die away into wisps.

"Looks like they're in at the six-inch wall," Helton said. "Time for me to go to work."

He walked briskly off toward Chief Byers.

"What did he mean by that?" Gerd asked.

"I don't know," Jack said,"but if we watch, we'll probably find out."

Helton motioned for Chief Byers to move one side of his headphones so he could hear. "Are you down to the mark?" he asked.

"On the button," Byers said. "We're backin' her out now."

"How long will it take you to blow down the temperature enough for me to go in there in a heat suit?" Helton asked." 'Bout twenty minutes, if I use the air changers," Byers answered without hesitation.

"Good," Helton said. "I'll go draw the gear."

Sweating and gasping for breath, Squint and Dave finally knocked off the last confining outcropping and were able to squeeze into the cavern. They were astonished at what they saw. Morrie and Jimmy heard the vibrohammers stop and came down the fissure on the run.

"Gnu! It's hot in here," Morrie said, then stopped short. "What shall we do?"

Jimmy said. Squint growled and wiped the sweat from his face. "Why, get as many sunstones as we can carry, before we all die of suffocation-stupid."

"Yeah, yeah!" Jimmy said excitedly. "And we'll keep this a secret and come back later, with breathing gear."

"Wait a minute," Dave said loudly. "Shut up, you guys. What's that noise?"

"What noise?" Squint asked. "Listen!" Dave said. They all fell silent.

"That noise," Dave said. "That popping and snapping noise. Sounds like it's coming from that rockfall over there." "Great Ghu!" Morrie wailed. "The mountain's gonna cave in on us."

"Maybe," Squint said, "but I'm gonna get some sunstones first. Let's get busy."

Tendrils of vapor trailed from the top of the tunnel opening and the walls still popped and crackled from the rapid cool-down as Phil Helton disappeared into the tunnel mouth, wearing a hot suit and carrying a snooper-phone in a heat-shielding container.

"Now what's he doing that for?" Gerd said. The little hillock where they stood was a grandstand seat from which to watch the entire affair.