e stream bed, keeping
close to the high bank.

A score of yards past the turning, intuition of danger made Dworn swerve
sharply. An instant later, the ground blew up almost in his face--the
bend had brought him into view, under the guns of the enemy above.

He wrenched the beetle around in a skidding turn and raced back for the
bend where the overhang afforded shelter. Another shell and another
crashed into places he had just left, and then he was safe--for the
moment.

But it was an uncomfortable spot. The caterpillar rumbling wrathfully on
the slope above him, couldn't see him as long as he hugged the bank,
undercut by the water that flowed here in the rainy season; but, by the
same token, he couldn't make a dash for safety without running the
gauntlet of a murderous fire in the all-too-narrow way the stream bed
offered. In open country, he would not have hesitated to count on his
ability to outmaneuver and outshoot the caterpillar ... but here he was
neatly trapped.

And it was nerve-racking to be unable to see what the enemy was about.
It seemed to have halted, judging the situation just as he had been
doing. Now, though, he heard its engine speed up again, and the grinding
of its treads came unmistakably closer. His ears strained to gauge its
advance as it came lurching down the slope, till it sounded only a few
feet away and Dworn braced himself to shoot fast and straight if it
started coming down over the bank. Then it paused again, and sat idling,
hoping no doubt that he would panic and show himself.

He didn't. The caterpillar's engine raced up once more and began to
labor under a heavy load. There was an increasing clatter of falling
stones. Then Dworn remembered the great digging-blade it carried, and
realized what it was going to try.

Ten feet to his right the bank began giving way. Tons of rubble
thundered into the gully. Dworn winced and moved away as far as he
dared. He heard the caterpillar back and turn, then it snarled with
effort once more and another section of the overhang caved in with a
grinding roar.

Inside minutes at this rate, it would either have driven him from his
refuge or buried him alive. Now it came rumbling forward for the third
time; rocks showered from the rim directly above his head, and he saw
the bank begin to tremble.

* * * * *

Dworn braced himself. Even as the wall of earth and rock began leaning
outward above him, he gave his engine