Raf was two streets away from the circling box but still able to keep it in sight when its easy glide stopped, and, in a straight line, it swooped toward a roof emitting a shrill, rising whistle. It rose again a few seconds later as if baffled, but it continued to hover at that point, keening forth its warning. The pilot reached[137] the next building, but a street still kept him away from the conical structure above which the box now hung.  
Undecided, he stayed where he was. Should he go down to street level and investigate? Before he had quite made up his mind he saw the foremost of the alien scouting party round into the thoroughfare below and move purposefully at the cone tower, weapons to the fore. Judging by their attitude, the box had run to earth there the prey they had been searching for.
 
But it wasn't to be so easy. With another eerie howl the machine soared once more and bobbed completely over the cone to the street which must lie beyond it. Raf knew that he could not miss the end of the chase and started on a detour along the roof tops which should bring him to a vantage point. By the time he had made that journey he found himself on a warehouse roof which projected over the edge of the river.
 
From a point farther downstream a small boat was putting out. Two of the aliens paddled while a third crouched in the bow. A second party was picking its way along the bank some distance away, both groups seemingly heading toward a point a building or two to the left of the one where Raf had taken cover.
 
He heard the shrilling of the box, saw it bobbing along a line toward the river. But in that direction there was only a mass of green. The end to the weird chase came so suddenly that he was not prepared, and it was over before he caught a good look at the quarry. Something moved down on the river bank and in that same instant the box hurtled earthward as might a spear. It struck, and the creature who had just crawled out—out of the ground as far as Raf could see—toppled into the stream. As the waters closed over the body, the box slued around and came to rest on the bank. The party in the boat sent their small craft flying toward the spot where the crawler had sunk.[138]
 
One of the paddlers abandoned his post and slipped over the side, diving into the oily water. He made two tries before he was successful and came to the surface with the other in tow. They did not try to heave the unconscious captive into the boat, merely kept the lolling head above water as they turned downstream once more and vanished from Raf's sight around the end of a pier, while the second party on the bank reclaimed the now quiet box and went off.
 
But Raf had seen enough to freeze him where he was for a moment. The creature which had popped out of the ground only to be struck by the box and knocked into the river—he would take oath on the fact that it was not one of the furred animals he had seen on the sea island. Surely it had been smooth-skinned, not unlike the aliens in conformation—one of their own kind they had been hunting down, a criminal or a rebel?
 
Puzzled, the pilot moved along from roof to roof, trying to pick up the trail of the party in the boat, but as far as he could now see, the river was bare. If they had come ashore anywhere along here, they had simply melted into the city. At last he was forced to use the homing beam, and it guided him back across the deserted metropolis to the field.
 
There was still activity about the globe; they were bringing in the loot from the warehouse, but Lablet and Hobart stood by the flitter. As the pilot came up to them, the captain looked up eagerly.
 
"What happened?"
 
Raf sensed that there had been some change during his absence, that Hobart was looking to him for an explanation to make clear happenings here. He told his story of the hunt and its ending, the capture of the stranger. Lablet nodded as he finished.
 
"That is the reason for this, you may depend upon it, Captain. One of their own people is at the bottom of it."[139]
 
"Of what?" Raf wanted to ask, but Soriki did it for him.
 
Hobart smiled grimly. "We are all traveling back together. Take off in the early morning. For some reason they wanted us out of the globe in a hurry—practically shoved us out half an hour ago."
 
Though the Terrans kept a watch on the larger ship as long as the light lasted, the darkness defeated them. They did not see the prisoner being taken aboard. Yet none of them doubted that sometime during the dusky hours it had been done.
 
It was barely dawn when the globe took off the next day, and Raf brought the flitter up on its trail, heading westward into the sea wind. Below them the land held no signs of life. They swept over the deserted, terraced city that was the gateway to the guarded interior, flew back over the line of sea islands. Raf climbed higher, not caring to go too near the island where the aliens had wrought their terrible vengeance on the trip out. And all four of the Terrans knew relief, though they might not admit it to each other, when once more Soriki was able to establish contact with the distant spacer.
 
"Turn north, sir?" the pilot suggested. "I could ride her beam in from here—we don't have to follow them home." He wanted to do that so badly it was almost a compulsion to make his hand move on the controls. And when Hobart did not answer at once, he was sure that the captain would give that very order, taking them out of the company of those he had never trusted.
 
But Lablet spoiled that. "We have their word, Captain. That anti-grav unit that they showed us last night alone—"
 
So Hobart shook his head, and they meekly continued on the path set by the globe across the ocean.
 
As the hours passed Raf's inner uneasiness grew. For some queer reason which he could not define to himself or explain to anyone else, he was now possessed by an urgency to trail the globe which tran[140]scended and then erased his dislike of the aliens. It was as if some appeal for help was being broadcast from the other ship, drawing him on. It was then that he began to question his assumption that the prisoner was one of them.
 
Over and over again in his mind he tried to re-picture the capture as he had witnessed it from the building just too far away and at slightly the wrong angle for a clear view. He would swear that the body he had seen tumble into the flood had not been furred, that much he was sure of. But clothing, yes, there had been clothing. Not—his mind suddenly produced that one scrap of memory—not the bandage windings of the aliens. And hadn't the skin been fairer? Was there another race on this continent, one they had not been told about?
 
When they at last reached the shore of the western continent and finally the home city of the aliens, the globe headed back to its berth, not in the roof cradle from which it had arisen, but sinking into the building itself. Raf brought the flitter down on a roof as close to the main holding of the painted people as he could get. None of the aliens came near them. It seemed that they were to be ignored. Hobart paced along the flat roof, and Soriki sat in the flyer, nursing his com, intent upon the slender thread of beam which tied them to the parent ship so many miles away.
 
"I don't understand it." Lablet's voice arose almost plaintively. "They were so very persuasive about our accompanying them. They were eager to have us see their treasures—"
 
Hobart swung around. "Somehow the balance of power has changed," he observed, "in their favor. I'd give anything to know more about that prisoner of theirs. You're sure it wasn't one of the furry people?" he asked Raf, as if hoping against hope that the pilot would reply in doubt.
 
"Yes, sir." Raf hesitated. Should he air his suspicions, that the captive was not of the same race as his cap[141]tors either? But what proof had he beyond a growing conviction that he could not substantiate?
 
"A rebel, a thief—" Lablet was ready to dismiss it as immaterial. "Naturally they would be upset if they were having trouble with one of their own men. But to leave now, just when we are on the verge of new discoveries—That anti-gravity unit alone is worth our whole trip! Imagine being able to return to earth with the principle of that!"
 
"Imagine being able to return to earth with our skins on our backs," was Soriki's whispered contribution. "If we had the sense of a Venusian water nit, we'd blast out of here so quick our tail fumes'd take off with us!"
 
Privately Raf concurred, but the urge to know more about the mysterious prisoner was still pricking at him, until he, contrary to his usual detachment, felt driven to discover all that he could. It was almost, but Raf shied away from that wild idea, it was almost as if he were hearing a voiceless cry for aid, as if his mind was one of Soriki's coms tuned in on an unknown wave length. He was angrily impatient with himself for that fantastic supposition. At the same time, another part of his mind, as he walked to the edge of the roof and looked out at the buildings he knew were occupied by the aliens, was busy examining the scene as if he intended to crawl about on roof tops on a second scouting expedition.
 
Finally the rest decided that Lablet and Hobart were to try to establish contact with the aliens once more. After they had gone, Raf opened a compartment in the flitter, the contents of which were his particular care. He squatted on his heels and surveyed the neatly stowed objects inside thoughtfully. A survival kit depended a great deal on the type of terrain in which the user was planning ............