Jill seemed to flinch a little.

"They're not using it at killing strength," said Lockley coldly.

"They're softening us up. Letting us find out we're frustrated and helpless, and then letting us think it over. I'll bet they intended the four of us to escape from that compost pit thing so we could tell about it! But we'll know, now, if we find dead men in rows in a wiped-out town, we'll know what killed them, and when they ask us politely to become their slaves, we'll know we'll have to do it or die!"

Jill waited. When he seemed to have finished, she said, "If they're monsters, do you think they want to enslave us?"

He hesitated, and then said with a grimace, "I've a habit, Jill, of looking forward to the future and expecting unpleasant things to happen. Maybe it's so I'll be pleasantly surprised when they don't."

"Suppose," said Jill, "that they aren't monsters. What then?"

"Then," said Lockley, "it's a cold war device, to find out if the other side in the cold war can take us over without our suspecting they're the ones doing it. Naturally those in this ship will blow themselves up rather than be found out."

"Which," said Jill steadily, "doesn't offer much hope for...."

She didn't say Vale's name. She couldn't. Lockley grimaced again.

"It's not certain, Jill. The evidence is on the side of the monsters.

But in either case the thing for us to do is get to the Army with what I've found out. I've had a stationary beam to test, however crudely.

The cordon must have been pushed back by a moving or an intermittent beam. It wouldn't be easy to experiment with one of those. Come on."

She stood up. She followed when he went on. They climbed steep hillsides and went down into winding valleys. The sun began to sink in the west. The going was rough. For Lockley, accustomed to wilderness travel, it was fatiguing. For Jill it was much worse.

They came to a sere, bare hillside on which neither trees nor brushwood grew. It amounted to a natural clearing, acres in extent.

Lockley swept his eyes around. There were many thick-foliaged small trees attempting to advance into the clear s.p.a.ce. He grunted in satisfaction.

"Sit down and rest," he commanded. "I'll send a message."

He broke off branches from dark green conifers. He went out into the clearing and began to lay them out in a pattern. He came back and broke off more, and still more. Very slowly, because the lines had to be large and thick, the letters S.O.S. appeared in dark green on the clayey open s.p.a.ce. The letters were thirty feet high, and the lines were five feet wide. They should show distinctly from the air.

"I think," said Lockley with satisfaction, "that we might get something out of this! If it's sighted, a 'copter might risk coming in after us." He looked at her appraisingly. "I think you'd enjoy a good meal."

"I want to say something," said Jill carefully. "I think you've been trying to cheer me up, after saying something to arouse me--which I needed. If the creatures aren't monsters, they'll never actually let anybody loose who's seen that they aren't. Isn't that true? And if it is--"

"We know of six men who were captured," insisted Lockley, "and I was one of them. All six escaped. Vale may have escaped. They're not good at keeping prisoners. We don't know and can't know unless it's mentioned on a news broadcast that he's out and away. So there's absolutely no reason to a.s.sume that Vale is dead."

"But if he saw them, when he was fighting them--"

"The evidence," insisted Lockley again, "is that he saw monsters. The only reason to doubt it is that they blindfolded four of us."

Jill seemed to think very hard. Presently she said resolutely, "I'm going to keep on hoping anyhow!"

"Good girl!" said Lockley.

They waited. He was impatient, both with fate and with himself. He felt that he'd made Jill face reality when--if this S.O.S. signal brought help--it wasn't necessary. And there was enough of grimness in the present situation to make it cruelty.

After a very long time they heard a faint droning in the air. There might have been others when they were trudging over bad terrain, and they might not have noticed because they were not listening for such sounds. There were planes aloft all around the lake area. They'd been sent up originally in response to a radar warning of something coming in from s.p.a.ce. Now they flew in vast circles around the landing place of that reported object. They flew high, so high that only contrails would have pointed them out. But atmospheric conditions today were such that contrails did not form. The planes were invisible from the ground.

But the pilots could see. When one patrol group was relieved by another, it carried high-magnification photographs of all the park, to be developed and examined with magnifying gla.s.ses for any signs of activity by the crew of the object from s.p.a.ce.

A second lieutenant spotted the S.O.S. within half an hour of the films' return. There was an immediate and intense conference. The lengths of shadows were measured. The size and slope and probable condition of the clearing's surface were estimated.

A very light plane, intended for artillery-spotting, took off from the nearest airfield to Boulder Lake.

And Lockley and Jill heard it long before it came in sight. It flew low, threading its way among valleys and past mountain-flanks to avoid being spotted against the sky. The two beside the clearing heard it first as a faint mutter. The sound increased, diminished, then increased again.

It shot over a minor mountain-flank and surveyed the bare s.p.a.ce with the huge letters on it. Lockley and Jill raced out into view, waving frantically. The plane circled and circled, estimating the landing conditions. It swung away to arrive at a satisfactory approach path.

It wavered. It made a half-wingover, and it side-slipped crazily, and came up and stalled and flipped on its back and dived....

And it came out of its insane antics barely twenty feet above the ground. It raced away as close as possible to touching its wheels to earth. It went away behind the mountains. The sound of its going dwindled and dwindled and was gone. It appeared to have escaped from a deliberately set trap.

Lockley stared after it. Then he went white.

"Idiot!" he cried fiercely. "Come on! Run!"

He seized Jill's hand. They fled together. Evidently, something had played upon the pilot of the light plane. He'd been deafened and blinded and all his senses were a shrieking tumult while his muscles knotted and his hands froze on the controls of his ship. He hadn't flown out of the beam that made him helpless. He'd fallen out of it.

And then he raced for the horizon. He got away. And it would appear to those to whom he reported that he'd arrived too late at the distress-signal. If fugitives had made it, they'd been overtaken and captured by the creatures of Boulder Lake, and there'd been an ambush set up for the plane. It was a reasonable decision.

But it puzzled the pilot's superior officers that he hadn't been allowed to land the plane before the beam was turned on him. He could have been paralyzed while on the ground, and he and his plane could have yielded considerable information to creatures from another world.

It was puzzling.

Lockley and Jill raced for the woodland at the clearing's edge.

Lockley clamped his lips tight shut to waste no breath in speech. The arrival and the circling of the plane had been a public notice that there were fugitives here. If the beam could paralyze a pilot in mid-air, it could be aimed at fugitives on the ground.... There could be no faintest hope....

Wholly desperate, Lockley helped Jill down a hillside and into a valley leading still farther down.

He smelled jungle, and muskiness, and decay, and flowers, and every conceivable discordant odor. Flashes of insane colorings formed themselves in his eyes. He heard the chaotic uproar which meant that his auditory nerves, like the nerves in his eyes and nostrils and skin, were stimulated to violent activity, reporting every kind of message they could possibly report all at once.

He groaned. He tried to find a hiding-place for Jill so that if or when the invaders searched for her, they would not find her. But he expected his muscles to knot in spasm and cramp before he could accomplish anything.

They didn't. The smell lessened gradually. The meaningless flashings of preposterous color grew faint. The horrible uproar his auditory nerves reported, ceased. He and Jill had been at the mercy of the unseen operator of the terror beam. Perhaps the beam had grazed them, by accident. Or it could have been weakened....

It was very puzzling.

CHAPTER 5

When darkness fell, Lockley and Jill were many miles away from the clearing where he had made the S.O.S. They were under a dense screen of leaves from a monster tree whose roots rose above ground at the foot of its enormous trunk. They formed a shelter of sorts against observation from a distance. Lockley had spotted a fallen tree far gone with wood-rot. He broke pieces of the punky stuff with his fingers. Then he realized that without a pot the bracken shoots he'd gathered could not be cooked. They had to be boiled or not cooked at all.

"We'll call it a salad," he told Jill, "minus vinegar and oil and garlic, and eat what we can."

She'd been pale with exhaustion before the sun sank, but he hadn't dared let her rest more than was absolutely necessary. Once he'd offered to carry her for a while, but she'd refused. Now she sat drearily in the shelter of the roots, resting.

"We might try for news," he suggested.

She made an exhausted gesture of a.s.sent. He turned on the tiny radio and tuned it in. There was no scarcity of news, now. A few days past, news went on the air on schedule, mostly limited to five-minute periods in which to cover all the noteworthy events of the world. Part of that five minutes, too, was taken up by advertising matter from a sponsor. Now music was rare. There were occasional melodies, but most were interrupted for new interpretations of the threat to earth at Boulder Lake. Every sort of prominent person was invited to air his views about the thing from the sky and the creatures it brought. Most had no views but only an urge to talk to a large audience. Something, though, had to be put on the air between commercials.