Somebody, somewhere, snickered, but became quickly silent and did not identify himself. “You know, Ravi,” said his commander at last, “that theory is crazy enough to be true. And I’m not sure if I want to see it tested… at least, until I get back to the mainland.” This celestial New York was just about as wide as the island of Manhattan, but its geometry was totally different. There were few straight thoroughfares; it was a maze of short, concentric arcs, with radial spokes linking them. Luckily, it was impossible to lose one’s bearings inside Rama; a single glance at the sky was enough to establish the north-south axis of the world. They paused at almost every intersection to make a panoramic scan. When all these hundreds of pictures were sorted out, it would be a tedious but fairly straightforward job to construct an accurate scale model of the city. Norton suspected that the resulting jigsaw puzzle would keep scientists busy for generations. It was even harder to get used to the silence here than it had been out on the plain of Rama. A city-machine should make some sound; yet there was not even the faintest of electric hums, or the slightest whisper of mechanical motion. Several times Norton put his ear to the ground, or to the side of a building, and listened intently. He could hear nothing except the pounding of his own blood. The machines were sleeping: they were not even ticking over. Would they ever wake again, and for what purpose? Everything was in perfect condition, as usual. It was easy to believe that the closing of a single circuit, in some patient, hidden computer, would bring all this maze back to life. When at last they had reached the far side of the city, they climbed to the top of the surrounding levee and looked across the southern branch of the Sea. For a long time Norton stared at the five-hundred-metre cliff that barred them from almost half of Rama—and, judging from their telescopic surveys, the most complex and varied half. From this angle, it appeared an ominous, forbidding black, and it was easy to think of it as a prison wall surrounding a whole continent. Nowhere along its entire circle was there a flight of stairways or any other means of access.

He wondered how the Ramans reached their southern land from New York. Probably there was an underground transport system running beneath the Sea, but they must also have aircraft as well; there were many open areas here in the city that could be used for landing. To discover a Raman vehicle would be a major accomplishment—especially if they could learn to operate it. (Though could any conceivable power source still be functioning, after several hundred thousand years?) There were numerous structures that had the functional look of hangars or garages, but they were all smooth and windowless, as if they had been sprayed with sealant. Sooner or later, Norton had told himself grimly, we’ll be forced to use explosives, and laser beams. He was determined to put off this decision to the last possible moment. His reluctance to use brute force was based partly on pride, partly on fear. He did not wish to behave like a technological barbarian, smashing what he could not understand. After all, he was an uninvited visitor in this world, and should act accordingly.

As for his fear—perhaps that was too strong a word; apprehension might be better. The Ramans seemed to have planned for everything; he was not anxious to discover the precautions they had taken to guard their property. When he sailed back to the mainland, it would be with empty hands.

Lieutenant James Pak was the most junior officer on board Endeavour, and this was only his fourth mission into deep space. He was ambitious, and due for promotion; he had also committed a serious breach of regulations. No wonder, therefore, that he took a long time to make up his mind.

It would be a gamble; if he lost, he could be in deep trouble. He could not only be risking his career; he might even be risking his neck. But if he succeeded, he would be a hero. What finally convinced him was neither of these arguments; it was the certainty that, if he did nothing at all, he would spend the rest of his life brooding over his lost opportunity. Nevertheless, he was still hesitant when he asked the Captain for a private meeting.

What is it this time? Norton asked himself, as he analysed the uncertain expression on the young officer’s face. He remembered his delicate interview with Boris Rodrigo; no, it wouldn’t be anything like that. Jimmy was certainly not the religious type; the only interests he had ever shown outside his work were sport and sex, preferably combined.

It could hardly be the former, and Norton hoped it was not the latter. He had encountered most of the problems that a commanding officer could encounter in this department—except the classical one of an unscheduled birth during a mission. Though this situation was the subject of innumerable jokes, it had never happened yet; of time. “Well, Jimmy, what is it?”

“I have an idea, Commander. I know how to reach the southern continent—even to the South Pole.”

“I’m listening. How do you propose to do it?”

“Er—by flying there.”

“Jimmy, I’ve had at least five proposals to do that—more if you count crazy suggestions from Earth. We’ve looked into the possibility of adapting our spacesuit propulsors, but air drag would make them hopelessly inefficient. They’d run out of fuel before they could go ten kilometres.”

“I know that. But I have the answer.”

Lt. Pak’s attitude was a curious mixture of complete confidence and barely suppressed nervousness. Norton was quite baffled; what was the kid worried about? Surely he knew his commanding officer well enough to be certain that no reasonable proposal would be laughed out of court.

“Well, go on. If it works, I’ll see your promotion is retroactive.”

That little half-promise, half-joke didn’t go down as well as he had hoped. Jimmy gave a rather sickly smile, made several false starts, then decided on an oblique approach to the subject.

“You know, Commander, that I was in the Lunar Olympics last year.”

“Of course. Sorry you didn’t win.”

“It was bad equipment; I know what went wrong. I have friends on Mars who’ve been working on it, in secret. We want to give everyone a surprise.”

“Mars? But I didn’t know…”

“Not many people do—the sport’s still new there; it’s only been tried in the Xante Sportsdome. But the best aerodynamicists in the solar system are on Mars; if you can fly in that atmosphere, you can fly anywhere.”

“Now, my idea was that if the Martians could build a good machine, with all their know-how, it would really perform on the Moon—where gravity is only half as strong.”

“That seems plausible, but how does it help us?”

Norton was beginning to guess, but he wanted to give Jimmy plenty of rope.

“Well, I formed a syndicate with some friends in Lowell City. They’ve built a fully aerobatic flyer with some refinements that no one has ever seen before. In lunar gravity, under the Olympic dome, it should create a sensation.”

“And win you the gold medal.”

“I hope so.”

“Let me see if I follow your train of thought correctly. A sky-bike that could enter the Lunar Olympics, at a sixth of a gravity, would be even more sensational inside Rama, with no gravity at all. You could fly it right along the axis, from the North Pole to the South—and back again.”

“Yes—easily. The one-way trip would take three hours, non-stop. But of course you could rest whenever you wanted to, as long as you kept near the axis.”

“It’s a brilliant idea, and I congratulate you. What a pity sky-bikes aren’t part of regular Space Survey equipment.”

Jimmy seemed to have some difficulty in finding words. He opened his mouth several times, but nothing happened. “All right, Jimmy. As a matter of morbid interest, and purely off the record, how did you smuggle the thing aboard?”