"We have never even studied one of their brains, you know, as they disintegrate upon the instant of cessation of normal functioning. But just as surely as you and I are sitting here, Admiral Martin, they will do something--something very efficient and exceedingly deadly. I have no idea what it will be. It may be mental, or physical, or both: they may be hidden away in some of our own ships already...." * * * * * Martin scoffed. "Impossible!" he exclaimed. "Why, those ships have been inspected to the very skin, time and time again!" "Nevertheless, they may be there," Stone went on, unmoved. "I am definitely certain of only one thing--if you install a laboratory aboard the flagship for me and equip it exactly according to my instructions, you will have one man, at least, whom nothing that the robots can do will take by surprise. Will you do it?" "I am convinced, really almost against my will." Martin frowned in thought. "However, convincing anyone else may prove difficult, especially as you insist upon secrecy." "Don't try to convince anybody!" exclaimed the scientist. "Tell them that I'm building a communicator--tell them I'm an inventor working on a new ray-projector--tell them anything except the truth!" "All right. I have sufficient authority to see that your requests are granted, I think." And thus it came about that when the immense Terrestrial Contingent lifted itself into the air Ferdinand Stone was in his private laboratory in the flagship, surrounded by apparatus and equipment of his own designing, much of which was connected to special generators by leads heavy enough to carry their full output. Earth some thirty hours beneath them, Stone felt himself become weightless. His ready suspicions blazed. He pressed Martin's combination upon his visiphone panel. "What's the matter?" he rasped. "What're they down for?" "It's nothing serious," the admiral assured him. "They're just waiting for additional instructions about our course in the maneuvers." "Not serious, huh?" Stone grunted. "I'm not so sure of that. I want to talk to you, and this room's the only place I know where we'll be safe. Can you come down here right away?" "Why, certainly," Martin assented. "I never paid any attention to our course," the physicist snapped as his visitor entered the laboratory. "What was it?" "Take-off exactly at midnight of June nineteenth," Martin recited, watching Stone draw a diagram upon a scratch-pad. "Rise vertically at one and one-half gravities until a velocity of one kilometer per second has been attained, then continue vertical rise at constant velocity. At 6:03:29 AM of June twenty-first head directly for the star Regulus at an acceleration of exactly nine hundred eighty centimeters per second. Hold this course for one hour, forty-two minutes, and thirty-five seconds; then drift. Further directions will be supplied as soon thereafter as the courses of the other fleets can be checked."