With an effort Lee forced herself to be fair. It might have done no good to lie, she conceded. But anyone with even a normal amount of simple courage would have tried. It was about two hours later when the siren went off again like a banshee wailing to a low-hanging moon. Men came running from all directions, shouting questions at the tops of their voices. A midget auto came skidding down the pirate ship's ramp, its driver standing on the accelerator. The car knifed through the swirling crowd, barely missing several people, and skidded to a dusty stop directly in front of Mantor. "_Radar signal!_" the driver yelled. "The search receiver picked up a signal that sounds like a destroyer's radar. It suddenly came in strong. Probably sneaked up on us from behind that damn moon. It's coming in fast and braking hard!" There was a mad scramble as the looters raced for their ship. Heavy-handed horseplay was forgotten. They knew they were helpless against a Navy destroyer. Their only hope lay in a fast getaway. Seconds could easily spell the difference between safety and defeat. In less than ten minutes the ship's locks were sealed and they fired off. As the flames roared out and the huge ship lifted swiftly it was obvious that they were throwing on all the fuel their jets could take. Marc Polder had faded back into the crowd at the first sound of the siren. As he stood watching the blastoff Lee joined him, hands in her pockets, looking more than ever like a boy. "Maybe my idea of asking for help wasn't so far-fetched," she said quietly. "Maybe the patrol might have been here in time. Maybe you wouldn't have had to tell them about the H.D.T." "Maybe," Marc answered without turning his eyes from the dwindling point of reddish light high in the dark sky. "And just by way of keeping the record straight," the girl went on in a voice that began to rasp, "you know as well as I do that the files don't list any H.D.T. It's under a code name." "Maybe," Marc replied in a noncommittal tone. The point of light in the sky suddenly turned blue. Lee was staring at it too, now. And she knew also what the change of color meant. Mantor had started to use the new fuel! * * * * * Suddenly there was a blinding flash. Lee cried out and staggered back, covering her eyes. Marc, who had closed his eyes when the color change came, took hold of the girl's arm. "I told you what would happen if they used the stuff," he said gently. "It's too hot for their jet chambers. It melts the walls. A lot of gas piles up in the tubes. The pressure pushes the fire back. And when it gets shoved back into the recoil chamber and you lose the protective layers of cold gas there--well, then you've got to look for your ship with an ionization gauge!