Raf fastened on the helmet and started away from the flitter. The buzzer which he had expected to roar in his ears was only a faint drone, and above it he could easily hear other sounds. Yet it was there, and he tested it by a series of loops away from the flyer. Each time as he came on the true beam he was rewarded by a deepening of the muted note. Yes, he could be a homer with that, and at the same time be alert to any other noise in his vicinity. "That's it!" He paid credit where it was due. But he was unable to break his long habit of silence. Something within him still kept him wary of the com-tech's open friendliness. None of the aliens approached the flitter as the shadows began to draw in. The procession of moving teams stopped, and most of the burden-bearing warriors withdrew to the globe and stayed there. Soriki pointed this out. "They're none too sure, themselves. Look as if they are closing up for the night." Indeed it did. The painted men had hauled up their ramp, the hatch in the globe closed with a definite snap. Seeing that, the com-tech laughed. "We have a double reason for a strict watch. Suppose whatever they've been looking for jumps _us_? They're not worrying over that it now appears." So they took watch and watch, three hours on and three hours in rest. When it came Raf's turn he did not remain sitting in the flitter, listening to the com-tech's heavy breathing, but walked a circular beat which took him into the darkness of the night in a path about the flyer. Overhead the stars were sharp and clear, glittering gem points. But in the dead city no light showed, and he was sure that no aliens camped there tonight. He was sleeping when Soriki's grasp on his shoulder brought him to that instant alertness he had learned on field maneuvers half the Galaxy away. "Business," the com-tech's voice was not above a whisper as he leaned over the pilot. "I think they are on the move." The light was the pale gray of pre-dawn. Raf pulled himself up with caution to look at the globe. The com-tech was right. A dark opening showed on the alien ship; they had released their hatch. He fastened his tunic, buckled on his equipment belt and helmet, strapped his boots. "Here they come!" Soriki reported. "One--two--five--no, six of them. And they're heading for the city. No dollies with them, but they're all armed." Together the Terrans watched that patrol of alien warriors, their attitude suggesting that they hoped to pass unseen, hurry toward the city. Then Raf slipped out of the flyer. His dark clothing in this light should render him largely invisible. Soriki waved encouragingly and the pilot answered with a quick salute before he sped after his quarry. 13 A HOUND IS LOOSED