While the Master's vengeance still flickered through the wastelands, his rebuilding had begun, and now he sat high and secure in his great Room of Power, that seemed to float as a miraculous campanulet of silver above the half mile peak of the Serene Tower. There was no sound in this room save the Master's breathing, but against its outer walls of glass lapped the purr and whisper and whine of millions of horsepower performing their appointed tasks. From the Southern Port came the drone of a great liner beating its way into the stratosphere, from where the thunder of its released rockets would come to him only as a faint orange streak is a dazzling sky. Through the air also came the hum of hovering taxicopters far below, the muted rumbling of the great moving streets and freightways and the mutter and crash and clang of building machines, all dying against this shell of glass. Through the mighty frame of the building itself quivered the vibrations of the giant factories, endlessly fabricating materials for more factories, more cities, more ships of the sky and sea, mere power and glory for the Master. But these vibrations, too, died in the protections of that tower top. Here, the Master assured himself, he was safe, safe alike in his life and in his power. For here were the telepathic controls of the ingenious and terrible robots, that kept the world securely his. Here also were some of the robots themselves, resembling neither machines nor men as they waited in everlasting patience and vigilance for his activating thought. And lest some danger creep upon him unaware, there were the Guard, faithful in their unleashed cruelty and mindless worship; there were the ray screens and thought detectors; and primitive but reassuring, there was the electric lock upon the elevator that was the sole entrance to this room. Only the vibrations of hate beat in, beat past locks and screens and rays, beat through glass and steel and plastic, beat gently, tirelessly, like ripples on a rock. Safe indeed was the Master, and powerful beyond all telling, but the Master was afraid. On the Master's desk the visiscreen glowed softly into life, and from it his secretary spoke. "Technician Heidkamp, special director Capitol Mecho-lab 43, desires an audience in the Room of Power to demonstrate the Time Visor to your Excellency." "Has it been inspected by the Director of Precautions?" The Master's fingers drummed nervously on his desk and he cast a sidelong glance behind him, although he knew that no human being could penetrate the Room of Power without his orders. "No, your Excellency, it bears a waiver with your signature." "No matter, have it inspected and report back at once." The visiscreen faded into lifelessness, and the Master returned to his musing. "No one in all the history of the world has ever been so powerful as I," he muttered, and yet he knew that in his heart there was fear, a fear which he had not the courage to face.