If Lieutenant McGuire could have erased from his mind the thought of the threat that hung over the earth he would have found nothing but intensest pleasure in the experiences that were his. But night after night they had heard the reverberating echoes of the giant gun speeding its messenger of death toward the earth, and he saw as plainly as if he were there the terrible destruction that must come where the missiles struck. Gas, of course; that seemed the chief and only weapon of these monsters, and Djorn, the elected leader of the Venus folk, confirmed him in this surmise. "We had many gases," he told McGuire, "but we used them for good ends. You people of Earth--or these invaders, if they conquer Earth--must some day engage in a war more terrible than wars between men. The insects are your greatest foe. With a developing civilization goes the multiplication of insect and bacterial life. We used the gases for that war, and we made this world a heaven." He sighed regretfully for his lost world. "These red ones found them, and our factories for making them. But they have no gift for working out or mastering the other means we had for our defense--the electronic projectors, the creation of tremendous magnetic fields: you saw one when we destroyed the attacking ships. Our scientists had gone far--" "I wish to Heaven you had some of them to use now," said the lieutenant savagely, and the girl, Althora, standing near, smiled in sympathy for the flyer's distress. But her brother, Djorn, only murmured: "The lust to kill: that is something to be overcome." The fatalistic resignation of these folk was disturbing to a man of action like McGuire. His eyes narrowed, and his lips were set for an abrupt retort when Althora intervened. "Come," she said, and took the flyer's hand. "It is time for food." * * * * * She took him to the living quarters occupied by her brother and herself, where opal walls and jewelled inlays were made lovely by the soft light that flooded the rooms. "Just one tablet," she said, and brought him a thin white disc, "then plenty of water. You must take this compressed food often and in small quantities till your system is accustomed." "You make this?" he asked. "But certainly. Our chemists are learned men. We should lack for food, otherwise, here in our underground home." He let the tablet dissolve in his mouth. Althora leaned forward to touch his hand gently. "I am sorry," she said, "that you and Djorn fail to understand one another. He is good--so good! But you--you, too, are good, and you fear for the safety of your own people." "They will be killed to the last woman and child," he replied, "or they will be captured, which will be worse." "I understand," she told him, and pressed his hand; "and if I can help, Lieutenant Mack Guire, I shall be so glad."