it would be a death ray, too!"

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 space. 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 l