Rees woke from a dream of falling.

His back was pressed against the inner face of the whale, his hands locked around folds of cartilage; cautiously he uncurled his fingers and worked the stiff joints.

What had woken him? He scanned the cavernous interior of the whale. Shafts of starlight still swept through the body like torch beams — - but, surely, more slowly than before. Was the whale coming to rest?

He turned to look out of the whale's face… and felt a tingle of wonder at the base of his skull. Peering in at him, not a dozen yards from where he stood, were the three eyes of a second whale. Its face was pressed to that of "his" whale, and he saw how the mouths of the two vast creatures worked in sympathetic patterns, almost as if they were speaking to each other.

Now the other whale peeled away, its flukes beating, and the view ahead cleared. Again wonder surged through Rees, causing him to gasp. Beyond the second whale was another, side on, forging through the air — and beyond that another, and another; as far as Rees's eyes could see, above him and below him, there was a great array of whales which swam through the Nebula. The school must have been spread through cubic miles: the more distant of them were like tiny lanterns illuminated by starlight.

Like a great, pinkish river, the whales were all streaming toward the Core.

From behind Rees there was a low grind, as if some great machine were stirring. Turning, he saw that the joint connecting the main body of the whale to its fluke section was swivelling; bones and muscles the size of men hauled at the mass of turning flesh. Soon the whale was banking around a wide arc, its flukes beating purposefully. The whale's rotation increased once more, turning the school of whales into a kaleidoscope of whirling flukes; and at last the whale settled into a place in the vast migration.

For hours the school forged on into increasing darkness. The stars at these depths were older, dimmer, their proximity increasing as the Core neared. Rees made out two stars so close they

almost touched: their tired fires were drawn out in great mounds, and they whirled around each other in a pirouette seconds long. Later the whales passed a massive star, miles across; its fusion processes seemed exhausted, but the iron of its surface, compressed by gravity, gave off a dull, somber glow. The surface was a place of constant motion: every few minutes a portion would subside, leaving a crater perhaps yards wide and a spray of molten particles struggling a few feet into the air. Smaller stars circled the giant in orbits of several minutes, and Rees was reminded of Hollerbach's orrery: here was another "solar system" model, made not of metal beads but of stars…

The school reached another collection of stars bound by gravity; but this time there was no central giant: instead a dozen small stars, some still burning, whirled through a complex, chaotic dance. At one moment it seemed two stars must collide… but no; they passed no more than yards apart, spun around and hurtled off in new directions. The motion of the star family showed no structure, no periodicity — and Rees, who in his time on the Raft had studied the chaotic aspects of the three-body problem, was not surprised.

Still the gloom deepened. A gathering blackness ahead told Rees they were nearing the Core. He remembered the Telescopic journey into the Nebula he had taken at the time of the revolt with that young Class Three — what was his name? Nead? Little had he dreamt that one day he would repeat the journey in person, and in such a fantastic fashion…

Again he thought briefly of Hollerbach. What would that old man give to be seeing these wonders? A mood of contentment, perhaps brought on by his memories, settled over Rees.

Now, as on his Telescopic journey, the mists of the Nebula's heart lifted away like veils from a face, and he began to make out the sphere of debris around the Core itself. Through breaks in the shell of rubble a pink light flickered.

Slowly Rees began to realize he was staring at his own death. What would get him first? The hard radiation sleeting from the black hole? Perhaps the tidal effects of the Core's gravitation would tear his head and limbs from his body… or, as the softer structure of the whale disintegrated, maybe he would find himself tumbling helpless in the air, baked or asphyxiated in the oxygen-starved atmosphere.

But still the odd mood of contentment lingered, and now he felt a slow, soothing music sound within his head. He let his muscles relax and he settled comfortably against the inner face of the whale. If this really were to be his death — well, at least it had been an interesting journey.

And perhaps, after all, death wouldn't be the final end. He recalled some of the simple religious beliefs of the Belt. What if the soul survived the body, somehow? What if his journey were to continue on some other plane? He was struck by a vision of a stream of disembodied souls streaking out into space, their flukes slowly beating—

Flukes? What the hell — ?

He shook his head, trying to clear it of the bizarre images and sounds. Damn it, he knew himself well enough to know that he shouldn't be facing death with an elegiac smile and a vision of the afterlife. He should be fighting, looking for a way out…

But if these thoughts weren't his own, whose were they? With a shudder he turned and stared at the bulge of brain around the whale's esophagus. Could the beast be semi telepathic? Were the images seeping into his head from that great mound, mere yards from him?

He remembered how the chanting of the Boney hunters had attracted the whales. Perhaps the chanting set up some sort of telepathic lure which baffled and attracted the whales. With a start he realized that the steady music in his head had the same structure, the same compelling rhythm and cyclical melodies, as the Boneys' song. It must be coming from outside him — though whether through his ears or by telepathic means he found it impossible to distinguish. So the Boneys, perhaps by chance, had found a way to make the whales believe they were swimming, not toward a slow death at the hands of tiny, malevolent humans, but toward—

What? Where did these whales, swimming to the Core, think they were going, and why were they so happy to be going there?

There was only one way to find out. He quailed at the thought of opening his mind to further violation; but he fixed his hands tightly around the cartilage, closed his eyes, and tried to welcome the bizarre images.

Again the whales streaked into the air. He tried to observe the scene as if it were a photograph before him. Were these things really whales? Yes; but somehow their bulk had been reduced drastically, so that they became pencil-shaped missiles soaring against minimal air resistance to… where? He struggled, compressing his eyes with the back of one hand, but it wouldn't come. Well, wherever it was, "his" whale felt nothing but delight at the prospect.

If he couldn't see the destination, what about the source?

Deliberately he lowered his head. The image in his mind panned down, as if he were tracking a Telescope across the sky.

And he saw the source of the whales' flight. It was the Core.

He opened gritty eyes. So the creatures were not plunging to their deaths; somehow they were going to use the Core to gain enormous velocities, enough to send them hurtling out—

— out, he realized with a sudden burst of insight, of the Nebula itself.

The whales knew the Nebula was dying. And, in this fantastic fashion, they were migrating; they would abandon the fading ruin of the Nebula and cross space to a new home. Perhaps they had done this dozens, hundreds of times before; perhaps they had spread among the nebulae in this way for hundreds of thousands of shifts…

And what the whales could do, surely man could emulate. A great wave of hope crashed over Rees; he felt the blood burn in his cheeks.