“Big cave,” Kerk grunted. “Slants back and down. What I was afraid of. Bomb dropped on that would just close it up. With no guarantee that anything sealed in it couldn’t eventually get out. We’ll have to see how far down it goes.”

There was enough heat in the cave now to use the infrared filters. The rock walls stood out harshly black and white as the advance continued.

“No signs of life since entering the cave,” the officer reported. “Gnawed bones at the entrance and some bat droppings. It looks like a natural cave-so far.”

Step by step the advance continued, slowing as it went. Insensitive as the Pyrrans were to psi pressure, even they were aware of the blast of hatred being continuously leveled at them. Jason, back in the ship, had a headache that slowly grew worse instead of better.

“Watch out!” Kerk shouted, staring at the screen with horror.

The cave was filled from wall to wall with pallid, eyeless animals. They poured from tiny side passages and seemed to literally emerge from the ground. Their front ranks dissolved in flame, but more kept pressing in. On the screen the watchers in the ship saw the cave spin dizzily as the operator fell. Pale bodies washed up and concealed the lens.

“Close ranks-flamethrowers and gas!” Kerk bellowed into the mike. Less than half of the men were alive after that first attack.

The survivors, protected by the flamethrowers, set off the gas grenades. Their sealed battle armor protected them while the section of cave filled with gas. Someone dug through the bodies of their attackers and found the pickup.

“Leave the bomb there and withdraw,” Kerk ordered. “We’ve had enough losses already.”

A different man stared out of the screen. The officer was dead. “Sorry, sir,” he said, “but it will be just as easy to push ahead as back as long as the gas grenades hold out. We’re too close now to pull back.”

“That’s an order,” Kerk shouted, but the man was gone from the screen and the advance continued.

Jason’s fingers hurt where he had them clamped to the chair arm. He pulled them loose and massaged them. On the screen the black-andwhite cave flowed steadily toward them. Minute after minute went by this way. Each time the animals attacked again, a few more gas grenades were used up.

“Something ahead-looks different,” the panting voice cracked from the speaker. The narrow cave slowly opened out into a gigantic chamber, so large the roof and far walls were lost in the distance.

“What are those?” Kerk asked. “Get a searchlight over to the right there.”

The picture on the screen was fuzzy and hard to see now, dimmed by the layers of rock in between. Details couldn’t be made out clearly, but it was obvious this was something unusual.