"Some risk. Those-who-lead may dislike what I must tell them. I ask again, would you hunt me down?"

"Here on an alien world, amid beings of such awesome power and such lack of faith in a kzin's peaceful intent?" The kzin's tail lashed once, emphatically. "No. But neither would I continue with the expedition."

"That will be suffident." Nessus trotted off, trembling visibly, following the guidelight.

"What's he scared of?" Teela complained. "He's done everything they told him to. Why would they be angry with him?"

"I think he's up to something," said Louis. "Something devious. But what?"

The blue light moved on. They followed it into an irridescent hemisphere …

Now the dome had vanished. From a triangle of couches, two humans and a kzin looked out into a tame jungle of brilliant alien plants, watching the approach of a strange puppeteer. Either the dome itself was invisible from inside, or the park scene was a projection.

The air smelled of many puppeteers.

The strange puppeteer pushed its way through a last fringe of hanging scarlet tendrils. (Louis remembered when he had thought of Nessus as "it". When had Nessus graduated to "him"? But, Speaker, a familiar alien, had been "him" from the beginning.) The puppeteer stopped there, just short of the presumed boundaries of the pearly dome. Its mane was silver where Nessus's was brown, and was neatly coiffeured in complex ringlets; but its voice was Nessus's thrilling contralto.

"I must apologize for not being present to greet you. You may address me as Chiron."

A projection, then. Louis and Teela murmured polite demurrers. Speaker-To-Animals bared his teeth.

"The one you call Nessus knows all that you are about to learn. His presence was required elsewhere. However, he mentioned your reactions on learning of our engineering skills."

Louis winced. The Puppeteer continued. "This may be fortunate. You will understand the better when you learn of our own reactions to a more ambitious work of engineering."

Half the dome went black.

Annoyingly, it was the side of the dome opposite to the Projected puppeteer. Louis found a control to turn his couch; but he reflected that he would have needed two' swiveled heads with independently operating eyes to watch both halves of the dome at once. The darkened side showed starry space forming a backdrop for a small, blazing disc.

A ringed disc. The scene was a blow-up of the holo in Louis Wu's pocket.

The light source was small and brilliant white, very like a view of Sol as seen from the general neighborhood of Jupiter. The ring was huge in diameter, wide enough to stretch halfway across the darkened side of the dome; but it was narrow, not much thicker than the light source at its axis. The near side was black and, where it cut across the light, sharp-edged. Its further side was a pale blue ribbon across space.

If Louis was growing used to miracles, he was not yet so blas as to make idiotic-sounding guesses. Instead he said, "It looks like a star with a ring around it. What is it?"

Chiron's reply came as no surprise.

"It is a star with a ring around it," said the puppeteer. "A ring of solid matter. An artifact."

Teela Brown clapped her hands and burst into giggles. She strangled the giggles after a few moments and managed to look wonderfully solemn; but her eyes glowed. Louis understood perfectly. He felt a touch of the same joy. The ringed sun was his/her private toy: a new thing in a mundane universe.

(Take Christmas ribbon, pale blue and an inch wide, the kind you use to wrap presents. Set a lighted candle on a bare floor. Take fifty feet of ribbon, and struig it in a circle with the candle at the center, balancing the ribbon on edge so that the inner side catches the candlelight.)

But the kzin's tail was lashing back and forth, back and forth.

(After all, that wasn't a candle in the middle. That was a sun!)

"By now you know," said Chiron, "that we have been moving north along the galactic axis for the past two hundred and four of your Earth years. In kzin years -"

"Two hundred and seventeen."

"Yes. During that time we have naturally observed the space ahead of us for signs of danger and the unexpected. We had known that the star EC-1752 was ringed with an uncharacteristically dense and narrow band of dark matter. It was assumed that the ring was dust or rock. Yet it was surprisingly regular.

"Some ninety days ago our fleet of worlds reached a position such that the ring occluded the star itself. We saw that the ring was sharply bounded. Further investigation revealed that the ring is not gas nor dust, nor even asteroidal rock, but a solid band of considerable tensile strength. Naturally we were terrified."

Speaker-To-Animals asked, "How were you able to deduce its tensile strength?"

"Spectroanalysis and frequency shifts gave us a relative difference in velocities. The ring is clearly rotating about its primary at 770 miles per second, a velocity high enough to compensate for the pull of gravity from the primary, and to provide an additional centripetal acceleration of 9.94 meters per second. Consider the tensile strength needed to prevent the structure from disintegrating under such a pull!"

"Gravity," said Louis.

"Apparently."

"Gravity. A touch less than Earth's. There's somebody living there, on the inner surface. Hooo," said Louis Wu, for the full impact was beginning to hit him, and the little hairs were rising along his spinal column. He heard the swish, swish of the kzin's tail cutting air.

It was not the first time men had met their superiors. Thus far men had been lucky …

Abruptly Louis stood up and walked toward the dome wall. It didn't work. The ring and the star receded before him until he touched a smooth surface. But he saw something he hadn't noticed before.

The ring was checkered. There were regular rectangular shadows along its blue back.

"Can you give us a better picture?"

"We can expand it," said the contralto voice. The G2 star jerked forward, then shot blazing off to the right, so that Louis was looking down on the lighted inner surface of the ring. Blurred as it was, Louis could only guess that the brighter, whiter areas might be cloud, that regions of faintly deeper blue might be land where lighter blue was sea.

But the shadowed areas were quite visible. The ring seemed to be laid out in rectangles: a long strip of glowing baby blue followed by a shorter strip of deep, navy blue, followed by another long strip of light blue. Dots and dashes.

"Something's causing those shadows," he said. "Something in orbit?"

"Yes, just that. Twenty rectangular shapes orbit in a Kemplerer rosette much nearer the primary. We do not know their purpose."

"You wouldn't. It's been too long since you had a sun. These orbiting rectangles must be there to separate night from day. Otherwise it would always be high noon on the ring."

"You will understand now why we called for your help. Your alien insights were bound to be of value."

"Uh huh. How big is the ring? Have you studied it much? Have you sent probes?"

"We have studied the ring as best we could without slowing our velocity and without otherwise attracting notice to ourselves. We have sent no probes, of course. Since they would have to be remotely controlled by hyperwave, such probes might be traced back to us."

"You can't track a hyperwave signal. It's theoretically impossible."

"Perhaps those who built the ring have evolved different theories."

"Mmm."

"But we have studied the ring with other instruments." As Chiron spoke, the scene on the dome wall changed to blacks and whites and grays. Outlines shifted and wavered. "We have taken photographs and holographs in all electromagnetic frequencies. If you are interested -"