. How long ago that had been they could not have told, but they
suspected that days of haze hung in between. Vye searched the sky. No
globes winking there--just the flyer alone.

He took his old seat behind the pilot, watched Hume test the relays
and responses in the quick run down of a man who has done this chore
many times before. But the other gave a little sigh of relief when he
finished.

"She's all right, we can lift."

Again they both looked aloft, half fearing to see those malignant
herders wink into being to forbid flight. But the sky was as serenely
clear of even a drifting cloud as they could hope. Hume pressed a
button and they arose vertically with an even progress totally unlike
the leap which had taken them out of Wass' camp.

Well above the cliff wall they hovered, and were able to see below the
round bowl of the valley prison. Hume touched controls, the flitter
descended slowly just above the center of the lake. And from this
position they were able to sight the other peculiarity of that body of
water, that it was perfectly oval in shape, far too perfect to be an
undeveloped product of nature. Hume took a round disk from his
equipment belt, fitted it carefully into a slot on the control board
and pressed the button below. Then he sent the flitter in a weaving
zigzag course well above the surface of the water, so that eventually
the flyer passed over every foot of its surface.

And from above, in spite of the turgid quality of the liquid, they
could see what did rest on the bottom of that oval. The wall with its
sharp corner which Vye had noted from shore level was only part of a
water covered erection. It made a design when seen from overhead, a
six-pointed star surrounding an oval and in the midst of that oval a
black blot which they could not identify.

Hume brought the flitter over in one last sweep. "That's it. We have a
full taping."

"What do you think it is?"

"A device set there by an intelligent being, and set a long time ago.
This valley wasn't arranged over night, six months ago--or even a year
ago. We'll have to let the experts tell us when and for what reason.
Now, let's head for home!"

He brought the flitter up and over the valley wall, flying southwest
so that they passed over the gap which was the main entrance to the
trap. And now he tried the com unit, endeavoring to pick up a signal
on which they could beam in for a safe ride.

"That's odd." Under Hume's control the dire