No chance of rescuing her! From a hundred airports the great Government airships had long since sailed into the skies, carrying those selected by the wheel at Washington for sacrifice to the Earth Giants. Only one chance remained. If Cliff had discovered the secret that had so long eluded them, surely he would reveal it to him now! Their quarrel was forgotten. Kay only knew that the woman he loved was even then speeding southward to be thrown to the maw of the vile monsters that held the world in terror. Surely Cliff would bend every effort to save her! Only a few hours had passed since Kay had stormed out of the laboratory in the Adirondacks in a rage when he was back on their little private landing field. He leaped from the plane and ran up the trail beside the lake between the trees. The cabin was dark; and, when Kay reached the laboratory he found it dark too. "Cliff! Cliff!" he shouted. No answer came, and with a sinking heart he snapped the button at the door. It failed to throw the expected flood of light through the interior. With shaking hand Kay pulled the little electron torch from his pocket, and its bright beam showed that the door was padlocked. He moved round to the window. The glass was unbreakable, but the ray from the torch showed that the interior of the laboratory had been dismantled, and the great top was gone. In those few hours Cliff, for reasons best known to himself, had removed the top, Kay's one hope of saving Ruth. And he was gone. * * * * * In that moment Kay went insane. He raved and cursed, calling down vengeance upon Cliff's head. Cliff's very motive was incredible. That he had deliberately removed the top in order that Ruth should die was not, of course, conceivable. But in that first outburst of fury Kay did not consider that. Presently Kay's madness burned itself out. There was still one thing that he could do. His plane, slow though it was, would carry him to the pampas. He could get fresh fuel at numerous bootleg petrol stations, even though the regulations against intersectional flight were rigid. With luck he could reach the pampas, perhaps before the sluggish monsters had fallen upon their prey. It was said that the victims sometimes waited for days! Something was rubbing against his leg, pricking it through his anklets. Kay looked down. A lady porcupine, with tiny new quills, was showing recognition, even affection, if such a spiny beast could be said to possess that quality. Somehow the presence of the beast restored Kay's mind to normal. "Well, he's left us both in the lurch, Susie," he said. "Good luck to you, beastie, and may you find a secure hiding place until your quills have grown." * * * * *