equipment isn't designed for close range work, but we've been doing the
best we can, tried everything from infra-red through ultra-violet. If
there is a ship out there I'm afraid it's invisible."

Beads of sweat sprinkled Heselton's forehead. "This is bad, Rogers.
Mighty bad." Nervously, he walked across to the right of the bridge and
stood, hands clasped behind his back, staring blankly out at blackness
and the scattered stars. "I know there is a ship out there, and I know
that a ship simply can't be invisible, not to radar _and_ optics."

"What makes you sure there is only one, sir?"

Heselton cracked his fists together. "My God, Rogers, you're right!
There might be ..."

The intercom clacked. "This is fire control again, sir. I think we've
got something on the radiation detectors."

"Good work, what did you find?"

"Slight radioactivity, typical of interstellar drive mechanisms,
somewhere off to our right. Can't tell exactly where, though."

"How far away is it?"

"I don't know, sir."

Heselton's hands dropped to his sides. "Thanks," he said, "for the
help."

His desk tv flashed into life with a picture of the smiling alien
commander. "This is the linguistics section, Admiral. The aliens
understand a fairly common galactic symbology, I believe we can
translate simple messages for you now."

"Ask him where the hell he is," Heselton snapped without thinking, then
instantly regretted it as the alien's face showed unmistakable surprise.

The alien's smile grew into an almost unbelievable grin. He turned
sideways to speak to someone out of sight of the camera and suddenly
burst into a series of roaring cackles. "He's laughing, sir." The
translator commented unnecessarily.

The joke was strictly with the aliens. Heselton's face whitened in quick
realization. "Rogers! They _didn't know_ that we can't see them!"

"Look, sir." The navigator pointed to the tv screen and a brilliantly
clear image of Big Joe shimmering against the galaxy, lit by millions of
stars. Every missile port, even the military numerals along her nose
were clearly visible.

"They're rubbing it in, Rogers. Showing us what we look like to them."
Heselton's face was chalk. "They could blast Big Joe apart, piece by
piece--the most powerful ship in the galaxy."

"Maybe," said Rogers, "the second most powerful."

Without answering, Heselton turned and looked out again at empty space
and millions of steady, unwinking stars. His mind formed a