By now the humans were having a hard time keeping from falling down the slope. They clung to the grass while the three advance guards slid down on their "backs" toward the mess in the hollow at the base.

"I'm getting down," Kickaha said. He turned and began sliding down on the seat of his pants. The others followed him. When the friction became too great on their buttocks, they dug in their heels to brake. Halfway down they had to halt and turn over so their bottoms could cool off. Their trouser seats were worn away in several spots.

"Did you see that water?" Kickaha said. He pointed to his right.

Anana said, "I thought I did. But I assumed it was a mirage of some sort."

"No. Just before we started down, I saw a big body of water that way. It must be about fifteen miles away, at least. But you know how deceiving distances are here."

Directly below them, about two hundred feet away, was the living logjam. The humans resumed their rolling but at an angle across the ever-steepening slope. McKay's helmet, Kickaha's bow and quiver, and Anana's beamer and axe, impeded their movements but they managed. They fell the last ten feet, landing on their feet or on all fours.

The trees paid them no attention. Apparently, the instinct to save their fellows was dominating the need to kill and eat. However, the plants were so closely spaced that there was no room for the five people to get through the ranks.

They looked up the hill. This side was vertical now and beginning to bulge at the top. Hot air radiated from the hill.

"The roots of the grass will keep that overhang from falling right away," Kickaha said. "But for how long? When it does come down, we'll be wiped out."

The plants moved toward the tangle, side by side, the tips of their branches touching. Those nearest the humans moved a little to their right to avoid bumping into them. But the outreaching tentacles made the humans nervous.

After five minutes, the apex of the hill was beginning to look like a mushroom top. It wouldn't be long before a huge chunk tore loose and fell upon them.

Anana said, "Like it or not, Kickaha, we have to use the beamer."

"You're thinking the same thing I am? Maybe we won't have to cut through every one between us and open ground. Maybe those things burn?"

Urthona said, "Are you crazy? We could get caught in the fire!"

"You got a better suggestion?"

"Yes. I think we should adjust the beamer to cutting and try to slice our way out."

"I don't think there's enough charge left to do that," Anana said. "We'd find ourselves in the middle of this mess. The plants might attack us then. We'd be helpless."

"Burn a couple," Kickaha said. "But not too near us."

Anana rotated the dial in the inset at the bottom of the grip. She aimed the weapon at the back of a tree five yards to her right. For a few seconds there was no result. Then the bark began smoking. Ten seconds later, it burst into flames. The plant did not seem immediately aware of what was happening. It continued waddling toward the tangle. But those just behind stopped. They must have smelled the smoke, and now their survival instinct-or program-was taking over.

Anana set three others on fire. Abruptly, the nearest ranks behind the flaming plants toppled. Those behind them kept on moving, rammed into them, and knocked a number down.

The ranks behind these were stopped, their tentacles waving. Then, as if they were a military unit obeying a soundless trumpet call to retreat, they turned. And they began going as fast as they could in the opposite direction.

The blazing plants had stopped walking, but their frantically thrashing tentacles showed that they were aware of what was happening. The flames covered their trunks, curled and browned the leaves, shot off from the leaf-covered stems projecting from the tops of the trunks. Their dozen eyes burned, melted, ran like sap down the trunk, hissed away in the smoke.

One fell and lay like a Yule log in a fireplace. A second later, the other two crashed. Their legs moved up and down, the broad round heels striking the ground.

The stink of burning wood and flesh sickened the humans.

But those ahead of the fiery plants had not known what was happening. The wind was carrying both the smoke and the pheromones of panic away from them. They continued to the jam until the press of bodies stopped them. Those in the front ranks were trying to pull up the fallen, but the lack of room prevented them.

"Burn them all!" Red Ore shouted, and he was seconded by his brother, Urthona.

"What good would that do?" Kickaha said, looking disgustedly at them. "Besides, they do feel pain, even if they don't make a sound. Isn't that right, Urthona?"

"No more than a grasshopper would," the Lord said.

"Have you ever been a grasshopper?" Anana said.

Kickaha started trotting, and the others followed him. The passage opened was about twenty feet broad, widening as the retreaters moved slowly away. Suddenly, McKay shouted, "It's falling!"

They didn't need to ask what it was. They sprinted as fast as they could. Kickaha, in the lead, was quickly left behind. His legs still hurt, and the pain in his chest increased. Anana took his hand and pulled him along.

A crash sounded behind them. Just in front of them a gigantic ball of greasy earth mixed with rusty grass-blades had slammed into the ground. It was a piece broken off and thrown upward by the impact. It struck so closely that they could not stop. Both plunged into it and for a moment felt the oily earth and the scratch of the blades. But the mass was soft enough to absorb the energy of their impact, to give way somewhat. It was not like running into a brick wall.

They got up and went around the fragment, which was about the size of a one-car garage. Kickaha spared a glance behind him. The main mass had struck only a few yards behind them. Sticking out of its front were a few branches, tentacles, and kicking feet.

They were safe now. He stopped, and Anana also halted.

The others were forty feet ahead of them, staring at the great pile of dirt that ringed the base of the hill. Even as they watched, more of the mushrooming top broke off and buried the previous fallen mass.

Perhaps a hundred of the trees had survived. They were still waddling away in their slow flight.

Kickaha said, "We'll snare us some of the trees in their rear ranks. Knock off some more apples. We're going to need them to sustain us until we can get to that body of water."

Though they were all shaken, they went after the trees at once. Anana threw her axe and McKay his helmet. Presently they had more fruit than they could carry. Each ate a dozen, filling their bellies with food and moisture.

Then they headed toward the water. They hoped they were going in the right direction. It was so easy to lose their bearings in a world of no sun and constantly changing landscape. A mountain used as a mark could become a valley within one day.

Anana, walking by Kickaha's side, spoke softly.

"Drop back."

He slowed down, with no reluctance at all, until the others were forty feet ahead. "What is it?"

She held up the beamer so that he could see the bottom of the grip. The dial in the inset was flashing a red light. She turned the dial, and the light ceased.

"There's just enough charge left for one cutting beam lasting three seconds at a range of sixty feet. Of course, if I just use mild burning or stun power, the charge will last longer."

"I don't think they'd try anything against us if they did know about it. They need us to survive even more than we need them. But when-if-we ever find Urthona's home, then we'd better watch our backs. What bothers me is that we may need the beamer for other things."

He paused and stared past Anana's head.

"Like them."