"Elmo, any sign of this on the schematic?"
"No, there's nothing. This is supposed to be a straight corridor with no turns or intersections."
Elmo seemed content to let Dyrkin run the squad. Dyrkin waved up the next man in line, a recruit with the minimal name of Kov. He indicated that the man should get in front of him. The routine was simple. They edged their way along the wall with weapons at the ready. When they reached the entrance, Kov ducked briefly and adjusted the grav on his boots. When he'd straightened, they both took a deep breath that was audible in everyone's helmet. Kov made a grav jump straight across the opening. At the same time, Dyrkin spun around and fired from the corner. Immediately afterward, Kov fired from the opposite side. The concussion blasts were like hammer blows in the confined space. Although their helmets protected their ears, their bodies were kicked by the shocks. Their lungs felt as if they were suddenly being hugged by a huge constrictor. Dust cascaded down from the roof of the tunnel.
The firing stopped; Dyrkin stepped back from the opening, putting up his MEW and letting it rest against his shoulder.
"Ain't nothing in there."
The others moved up and peered into the opening. Dyrkin had been right. There was nothing in there except a pile of dark blue hexagonal cargo containers and a rack of gleaming new chiba frames, presumably waiting to have the sacs of intelligent goop fitted to them. Glowing scars of residual heat from the firing crisscrossed the walls. One of the containers had fallen and burst open. Its contents, a kind of gray packing fiber, had spilled out and were burning, giving off oily smoke.
"Don't touch any of that stuff. It's probably booby-trapped."
Two explosions came from somewhere else in the tunnel system. Some of the men ducked. More dirt fell from the tunnel ceiling. A meter-square section detached itself and crashed to the floor. Everyone froze. In tunnel clearing, the other hazard, apart from the enemy, was cave-in. This planet was so young and unstable that tunneling into it was a dubious business at the best of times. The constant low-level quakes meant that the best reinforced tunnel was prone to collapse even without a fire-fight inside it. The men waited tensely. There were no further rockfalls.
"Did anybody think that the Yal's best bet would be to wait until we were all inside and then blow the whole system?"
"I don't want to hear that talk." There was no authority in Elmo's voice. It was pure fear.
Dyrkin slung his weapon over his back. "You want that we should move on?"
The squad pressed on deep into the hill. There were sounds of firing and more explosions from other parts of the system, but nothing engaged them except a handful of miggies that dropped from the ceiling and were quickly dispatched. At regular intervals, wafts of scalding hot air washed down the tunnel. These only helped to accentuate the feeling that they were parasites in the bowels of some monstrous beast. Every step was racked with tension. Just because nothing had happened so far didn't mean it couldn't happen at any moment. The troopers, particularly the new recruits, flinched at every sound and movement. Already frayed nerves were being stretched to their limits. The prolonged stress involved in a search-and-destroy mission was bad enough in the open. In these claustrophobic tunnels, it was close to unbearable.
Dyrkin called another halt. Up ahead, there was what looked like a yellow glow in their redscoped visors. As far as they could see, the tunnel was opening out into a larger lighted space. The air had become very warm, so warm that it was starting to interfere with the function of the redscopes. The walls were now pulsing with a blood-red light, and the men were pouring sweat. The yellow glow seemed to be the source of it all. Nobody had any particular desire to be the first to find out exactly what it was. Finally, when Elmo offered no suggestions, let alone orders, Dyrkin beckoned to Hark and Renchett.
"Okay, let's go and see what we got here."
The three of them walked slowly forward, silhouetted against the yellow glow. Their weapons were held in front of them, away from their bodies, ready to fire at the widest possible sweep.
"When the tunnel opens out, keep on going. Hark, go to the left; Renchett, you go to the right. Look for cover and hit it. Best cut out your redscopes; that yellow light's going to blind us."
For a moment, the three men couldn't see, but then their eyes adjusted to regular light. Now that they weren't looking at heat, the yellow was little more than a suffused purple glow.
"That's plasma."
"It must be a main energy interface." Renchett halted. "Then it's got to be defended." "So let's go in and find out," Dyrkin said. "Do we have to?" Renchett said. "You got a better idea?" "No."
The spectacle that greeted them was little short of awesome. The tunnel had opened out into a wide, high-ceilinged, roughly circular cavern that seemed to be at least partly natural. The centerpiece was a tall translucent column that rose for the fiill height of the cavern and then vanished through the roof. A massive charge of plasma was pulsing up it. This was the source of the purple glow. In addition to the channeled plasma, white flares of secondary energy flickered on the outside of the power stack. The base of the column was a large containment sphere of dull black, extradense metal. It was supported by five heavy-duty grav pumpers. Without their aid, the sphere would simply have sunk into the ground and gone on sinking until it reached the center of the planet. The sphere had to be unbelievably massive. It contained what was, in effect, a miniature sun. It was banded by an intricate system of interconnected subducts. Below the sphere, the ducts ran out and away, across the floor in a sunburst that extended all the way to the walls of the cavern. These were also attended by outward ripples of dancing static. As Dyrkin had guessed, it was a major energy interface. "Mother! It's big!"
"This sucker could power a couple of firetowers." "Move it!"
There was no time to stand and stare. Renchett and Hark peeled off as they came out of the tunnel, just as Dyrkin had instructed. Hark spotted a pile of the hexagonal containers that seemed to be a standard item with the Yal. He ran for them, jumping the ducts as he went. When there were no more ducts, he dived and rolled. So far, there was no one shooting at them.
In position behind the containers, Hark tentatively called out to Dyrkin. "Nothing so far. You think this place is empty?"
The plasma was crackling in their helmets.
"Seems hard to believe they'd just leave it."
Renchett came in. "I don't like it."
Hark carefully studied the cavern. Other tunnels ran into it at regular intervals all around its circumference. The spaces in between them were taken up with racks of what, alien as it was, had to be control and monitoring equipment. A gantry, constructed from one molded piece of an ultrahard ceramic, ran around the containment sphere, some three meters above the ground. A broad ramp of the same material ran down from the gantry and into the mouth of the widest of the intersecting tunnels. Where the ramp and the gantry joined, there was a huge black chair. It appeared to have been contoured for some large, angular multilegged creature.
Renchett hissed in his helmet. "You know what that is? That contour chair?"
"What is it?"
"It's Yal. It was built for a Yal. There's been a Yal here."
There was almost reverence in his voice. Most humans never so much as came close to a Yal. To be where one might recently have been was sufficient to inspire awe.