his throat; the odor was faint and could not have turned the most sensitive of stomachs, but Horza had

known what it meant.

“Think we can mend it." Wubslin asked. Horza shook his head.

“Probably not. This happened once on a yearly test when I was here before. We powered up in the wrong sequence and blew that

same

cable-run; if they’ve done what we did there’ll be worse damage further down, in the deeper levels. Took us weeks to

repair it." Horza shook his

head. “Damn," he said.

“I guess it was pretty smart of those Idirans to figure out as much as they did," Wubslin said, opening his visor to reach

in and scratch his

head awkwardly. “I mean, to get this far."

“Yes," Horza said, kicking a large transformer. “Too goddamn smart."

They made a brief search of the station complex, then gathered again in the main cavern and crowded round the jury-rigged

mass sensor

Wubslin had removed from the

Clear Air Turbulence.

Wires and light-fibers were tangled about it, and attached to the top of the machine was

a cannibalized screen from the ship’s

bridge, now plugged directly into the sensor.

The screen lit up. Wubslin fiddled with its controls. The screen hologram showed a diagrammatic representation of a sphere,

with three

axes shown in perspective.

“That’s about four kilometers," Wubslin said. He seemed to be talking to the mass sensor, not the people around it. “Let’s

try eight…." He

touched the controls again. The number of lines on the axes doubled. One very faint smudge of light blinked

near the edge of the display.

“Is that it." Dorolow said. “Is that where it is."

“No," Wubslin said, fiddling with the controls again, trying to get the little patch of light to become clearer. “Not dense

enough." Wubslin

doubled the range twice more, but only the single trace remained, submerged in clutter.

Horza looked round, orienting himself with the grid pattern shown on the screen. “Would that thing be fooled by a pile of

uranium."

“Oh yeah," Wubslin said, nodding. “The power we’re putting through it, any radiation will upset it a bit. That’s why we’re

down to roughly thirty

kilometers maximum anyway, see. Just because of all this granite. Yeah, if there’s a reactor, even

an old one, it’ll show up when the sensor’s

reader waves get to it. But just like this, as a patch. If this Mind’s only fifteen

meters long and weighs ten thousand tons, it’ll be really bright. Like

a star on the screen."

“OK," Horza said. “That’s probably just the reactor down at the deepest service level."

“Oh," Wubslin said. “They had reactors, too."

“Back-up," Horza said. “That one was for ventilation fans if the natural circulation couldn’t cope with smoke or gas. The

trains have reactors,

too, in case the geothermal failed." Horza checked the reading on the screen with the built-in mass

sensor in his suit, but the faint trace of the

back-up reactor was out of its range.

“Should we investigate this one." Wubslin asked, his face lit by the glowing screen.

Horza straightened up, shaking his head. “No," he said wearily. “Not for now."

They sat in the station and had something to eat. The station was over three hundred meters long and twice the width of the

main tunnels. The

metal rails the Command System trains ran on stretched across the level floor of fused rock in double tracks,

appearing from one wall through

an inverted U and disappearing through another, toward the repair and maintenance area. At

either end of the station there were sets of

gantries and ramps which rose almost to the roof. Those provided access to the

two upper floors of the trains when they were in the station,

Horza explained when Neisin asked about them.

“I can’t wait to see these trains," Wubslin mumbled, mouth full.

“You won’t

be

able to see them if there’s no light," Aviger told him.

“I think it’s intolerable that I have to go on carrying all that junk," the drone said. It had set the equipment-loaded pallet

down. “And now I’m

told I have to carry even more weight!"

“I’m not that heavy, Unaha-Closp," said Balveda.

“You’ll manage," Horza told the machine. With no power the only thing they could do was use their suits’ AG to float along

to the next station;

it would be slower than the transit tube, but quicker than walking. Balveda would have to be carried

by the drone.

“Horza… I was wondering," Yalson said.

“What."

“How much radiation have we all soaked up recently."

“Not much." Horza checked the small screen inside his helmet. The radiation level wasn’t dangerous; the granite around them

gave off a

little; but even if they hadn’t been suited up, they’d have been in no real danger. “Why."

“Nothing." Yalson shrugged. “Just with all these reactors, and this granite, and that blast when the bomb went off in the

gear you vac’d from

the

CAT

… well, I thought we might have taken a dose. Being on the Megaship when Lamm tried to blow it apart didn’t help, either.

But if you

say we’re OK, we’re OK."

“Unless somebody’s particularly sensitive to it, we haven’t got much to worry about."

Yalson nodded.

Horza was wondering whether they should split up. Should they all go together, or should they go in two groups, one down each

of the foot

tunnels which accompanied the main line and the transit tube. They could even split up further and have somebody

go down each of the six

tunnels which led from station to station; that was going too far, but it showed how many possibilities

there were. Split up, they might be better

placed for a flanking attack if one group encountered the Idirans, though they

wouldn’t initially have the same firepower. They wouldn’t be

increasing their chances of finding the Mind, not if the mass

sensor was working properly, but they would be increasing their chances of

stumbling into the Idirans in the first place.

Staying together, though, in the one tunnel, gave Horza a feeling of claustrophobic foreboding. One

grenade would wipe them

out; a single fan of heavy laser-fire would kill or disable all of them.

It was like being set a cunning but unlikely problem in one of the Heibohre Military Academy’s term exams.

He couldn’t even decide which way to head. When they’d searched the station, Yalson had seen marks in the thin layer of dust

on the foot-

tunnel floor leading to station five, which suggested the Idirans had gone that way. But ought they to follow,

or should they go in the opposite

direction. If they followed, and he couldn’t convince the Idirans he was on their side,

they’d have to fight.

But if they went in the other direction and turned the electricity on at station one, they’d be giving power to the Idirans

as well. There was no

way of restricting the energy to one part of the Command System. Each station could isolate its section

of track from the supply loop, but the

circuitry had been designed so that no single traitor—or incompetent—could cut off

the whole System. So the Idirans, too, would have use of

the transit tubes, the trains themselves and the engineering workshops….

Better to find them and try to parley; settle the issue one way or the

other.

Horza shook his head. This whole thing was too complicated. The Command System, with its tunnels and caverns, its levels and

shafts, its

sidings and loops and cross-overs and points, seemed like some infernal closed-circuit flow chart for his thoughts.

He would sleep on it. He needed sleep now, like the rest of them. He could sense it in them. The machine might get run down

but it didn’t

need sleep, and Balveda still seemed alert enough, but all the rest were showing signs of needing a deeper rest

than just sitting down.