"If you scream now--" Abruptly, he made a short, chopping motion with his fist and the girl slumped unconscious. He shouldered her and began a careful approach. There was still a hundred feet to cover, the sky was growing lighter every minute, but the shadowy figure by his ship remained motionless. Brace stood in the shadow of the fin of a neighboring ship and turned plans over in his mind. It was no use. During that whole hundred feet he would be outlined against the sky. Then a sound tensed him, the whine of a sand car behind him. He crouched low, prepared to duck. This was it. Nobody on Titan had sand cars but the S.P. The miners used big ato-tractors. * * * * * Brace lunged around the edge of the fin to shield himself from the oncoming lights. The sand car whizzed past him and hissed to a smooth stop. They had seen him. Brace spun and ran, sand spurting behind him. He skidded under the huge belly of one ship, scrambled across to another-- Something crackled in the air--dust motes or insects caught in the S.P. ray--and suddenly-molten sand bubbled and spat behind him. [Illustration: _The sand suddenly bubbled and spat behind him._] But the blast was not followed by a closer one and Brace realized they were only shooting at random; he heard the ray hissing in another direction. He hurtled down the next alley and then forced himself to slow down to a shuffling run as he neared his own ship. His sprinting feet would leave too obvious tracks. Near the stern of his ship he stopped, his fingers fumbling over the smooth side, at last finding the knob. He shoved it inward. If the port squeaked--if one of the S.P. men came around the side of the ship--But the port didn't squeak. It opened silently. And Brace stepped in. He pressed another button, and the port closed. He was in. Brace walked swiftly to his cabin, opened the door and dropped the unconscious girl on his bunk. Quickly, he stripped off his coat and shirt and mussed his hair. The catch on one of his shoes stuck and he cursed as he ripped it off. Breathing rapidly, he waited for the sound of the buzzer, and when it came, he snatched up his heavy coat and threw it over his shoulders. As he stepped into the companionway, another cabin door opened and another figure, hastily coated stepped out. "I'll get it!" Brace growled. The other, startled, looked at him and said, "Yes, sir." Brace pushed past him, turned into another companionway and walked to the main fork. He pressed a stud and the inner door opened. Stepping into the compartment, he pressed another stud, watched the inner door close and the outer one open. He gulped to equalize the change in air pressure in his ears. * * * * * An S.P. man flicked on a light and shined it full in Brace's face. Brace touched a button and flooded the entire port with light. "What do you want?" he snapped. "I'm not blasting off for two hours! Come back in an hour!"