ate of affairs between the
Com-Pubs and the United Nations being one of highly armed truce,
"unauthorized traffic" meant nothing more or less than spies.

But on August 19th, 2037, Thorn Hard was off duty. Decidedly so. He
was sitting on top of Mount Wendel, in the Rockies; he had a
ravishingly pretty girl sitting on the same rock with him, and he was
looking at the sunset. The plane behind him was an official Watch
plane, which civilians are never supposed to catch a glimpse of. It
had brought Thorn Hard and Sylva West to this spot. It waited now,
half-hidden by a spur of age-eroded rock, to take them back to
civilization again. Its G.C. (General Communication) phone muttered
occasionally like the voice of conscience.

[Illustration:]

The colors of the mountain changed and blended. The sky to westward
was a glory of a myriad colors. Man and girl, high above the world,
sat with the rosy glow of dying sunlight in their faces and watched
the colors fade and shift into other colors and patterns even more
exquisite. Their hands touched. They looked at each other. They
smiled queerly, as people smile who are in love or otherwise not quite
sane. They moved inevitably closer....

And then the G.C. phone barked raucously:

"All Watch planes attention! Urgent! Extreme high-level traffic
reported seven-ten line bound due east, speed over one thousand. All
Watch planes put out all detectors and use extra vigilance. Note: the
speed, course, and time of report of this traffic checks with Com-Pub
observations of moving objects approaching Earth from Mars. This
possibility should be considered before opening fire."

Thorn Hard stiffened all over. He got up and swung down to the stubby
little ship with its gossamer-like wings of cellate. He touched the
report button.

"Plane 257-A reporting seven-ten line. Thorn Hard flying. On Mount
Wendel, on leave. Orders?"

He was throwing on the screens even as he reported. And the vertical
detector began to whistle shrilly. His eyes darted to the dial, and he
spoke again.

"Added report. Detector shows traffic approaching, bound due east,
seven hundred miles an hour, high altitude.... Correction; six-fifty
miles. Correction; six hundred." He paused. "Traffic is decelerating
rapidly. I think, sir, this is the reported ship."

* * * * *

And then there was a barely audible whining noise high in the air to
the west. It grew in volume and changed in pitc