but that's the best I can say."

"Sir," another voice chimed in, "this is fire control. We've got our directional antennas on the thing. It's either directly right or directly left of the ship, matching speed with us exactly."

"Either to our right or left?"

"That's the best we can do, sir, without radar help."

"Admiral, sir," the lieutenant who had first reported the signal came running back. "Judging from the frequency and strength, we think it's probably less than a hundred miles away."

"Less than a hundr ..."

"Of course, we can't be positive, sir."

Heselton whirled back to the intercom. "Radar! That thing is practically on our necks. What the hell's the matter with that equipment...?"

The radar commander's voice showed distinct signs of strain. "Can't help it, Admiral. The equipment is working perfectly. We've tried the complete range of frequencies, twenty-five different sets are in operation, we're going blind looking. There is absolutely nothing, nothing at all."

For a moment the bridge was silent, except for the clacking-grunting from the overhead speaker which, if anything, sounded louder than before.

"It's tv, sir!" The radio lieutenant came running in again. "We've unscrambled the image. Here!" The communications screen on Heselton's desk glowed for a moment, then flashed into life.

The figure was clearly alien, though startlingly humanoid—at least from the waist up, which was all that showed in the screen. A large mouth and slightly bulging eyes gave it a somewhat jovial, frog-like demeanor. Seated at a desk similar to Heselton's, wearing a gaudy uniform profusely strewn with a variety of insignia, it was obviously Heselton's counterpart, the commander of an alien vessel.

"Hmmm, looks like we've contacted a new race. Let's return the call, Lieutenant." A tiny red light glowed beneath a miniature camera on Heselton's desk and almost at once the alien's face registered obvious satisfaction. It waved a six-fingered hand in an unorthodox, but friendly, greeting.

Heselton waved back.

The alien then pointed to his mouth, made several clacking-grunting sounds, and moved a hand on his desk. The scene switched to another alien standing in front of what looked like a blackboard, with a piece of chalk in his hand. The meaning was clear.

"Lieutenant, have this transmission switched to the linguistics section. Maybe those guys can work some sort of language." The screen blanked out. Heselton leaned back, tense, obviously worried. Hesitantly, he reached out and touched a button on the intercom.

"Astronomy."

"Professor, there's a ship right next door somewhere that should stand out like King Kong in a kindergarten."

"I know, Admiral. I've been listening to the intercom. Our optical 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.