All this had happened in such a short space of time that the Saylor brothers must have had only a bare realization of what was going on. But by the time the "yo-yo" was flung at them again, this time with better calculations, they managed to put the firmly held asteroid between them and the deadly missile. But it was clumsy evasion, for the asteroid was several times as massive as the ship which was towing it, and its inertia was great. And as soon as the little ship came spinning back to rest, Bob flung the hauler to a new vantage point and again the "yo-yo" snapped out. And this time--collision! Bob yelled as he saw the stern section of the Saylor brothers' ship crumple like tissue paper crushed between the hand. The dumbbell-shaped ship, smaller, and therefore stauncher due to the principle of the arch, wound up again, wobbling a little. It had received a mere dent in its starboard half. Starre was chortling with glee. Queazy whispered, "Attaboy, Bob! This time we'll knock 'em out of the sky!" The "yo-yo" came to rest and at the same moment a gong rang excitedly. Bob knew what that meant. The Saylor brothers were trying to establish communication. Queazy was across the room in two running strides. He threw in the telaudio and almost immediately, Wally Saylor's big body built up in the plate. Wally Saylor's face was quivering with wrath. "What do you damned fools think you're trying to do?" he roared. "You've crushed in our stern section. You've sliced away half of our stern jets. Air is rushing out! You'll kill us!" "Now," Bob drawled, "you're getting the idea." "I'll inform the Interplanetary Commission!" screamed Saylor. "_If_ you're alive," Bob snarled wrathfully. "And you won't be unless you release the asteroid." "I'll see you in Hades first!" "Hades," remarked Bob coldly, "here you come!" He snapped the hauler into its mile-a-second speed again, stopped it at zero. And the "yo-yo" went on its lone, destructive sortie. For a fraction of a second Wally Saylor exhibited the countenance of a doomed man. In the telaudio plate, he whirled, and diminished in size with a strangled yell. The "yo-yo" struck again, but Bob Parker maneuvered its speed in such a manner that it struck in the same place as before, but not as heavily, then rebounded and came spinning back with perfect, sparkling precision. And even before it snugged itself into its berth, it was apparent that the Saylor brothers had given up. Like a wounded terrier, their ship shook itself free of the asteroid, hung in black space for a second, then vanished with a flaming puff of released gravitons from its still-intact jets. The battle was won! * * * * * As soon as the hauler had grappled itself onto the prized asteroid, Bob Parker jumped to his feet with a grin on his face as wide as the void. Queazy grabbed his arm and pounded his shoulder. Bob shook him off, losing his elation.