Half an hour later, as the rain swept in from the sea, Raf knew that they would not have to try. His head went up, his face eager. He had known that sound too long and too well ever to mistake it--the drone of a flitter motor cutting through the swish of the falling water. Some trick of the cliffs behind them must be magnifying and projecting the sound, for he could not sight the machine. But it was coming. He whirled to Dalgard, only to see that the other was on his feet and had taken up his spear. "It is the flitter! Soriki heard--they're coming!" Raf hastened to assure him. For the last time he saw Dalgard's slow, warm smile, clearer than he had ever seen it before. Then the scout turned and trotted away, toward a fringing rock wall. Before he dropped out of sight behind that barrier he raised the spear in salute. "Swift and fortunate voyaging!" He gave the farewell of Homeport. Then Raf understood. The colonist meant just what he had said: he wanted no contact with the space ship. To Raf he had owed a debt and now that was paid. But the time was not yet when the men of Astra and the men of Terra should meet. A hundred years from now perhaps--or a thousand--but not yet. And remembering what had summoned the flitter winging toward him, Raf drew a deep breath. What would the men of Astra accomplish in a hundred years? What could those of Terra do to match them in knowledge? It was a challenge, and he alone knew just how much of a challenge. Homeport must remain his own secret. He had been guided to this place, saved by the mermen alone. Dalgard and his people must not exist as far as the crew of the _RS 10_ were concerned. For the last time he experienced the intimacy of the mind touch. "That is it--brother!" Then the sensation was gone as the black blot of the flitter buzzed out of the clouds. From behind the rocks Dalgard watched the pilot enter the strange machine. For a single moment he had an impulse to shout, to run forward, to surrender to his desire to see the others, the ship which had brought them through space and would, they confidently believed, take them back to the Terra he knew only as a legend of the past. But he mastered that desire. He had been right. The road had already forked and there was no going back. He must carry this secret all the rest of his life--he must be strong-willed enough so that Homeport would never know. Time--give them time to be what they could be. Then in a hundred years--or a thousand--But not yet! * * * * * "Nobody today is telling better stories of straight-forward interstellar adventure." --_New York Herald-Tribune_ When Raf Kurbi's Terran spaceship burst into unexplored skies of the far planet Astra and was immediately made welcome by the natives of a once-mighty metropolis, Kurbi was unaware of three vital things: