"Relax," came a voice in Arcot's head, a low, droning voice, a voice of command. "Sleep," it added. Arcot felt himself floating down an infinite shaft, on some superflying suit that did not pull at him with its straps, just floating down lightly, down and down and down. Suddenly he reached the bottom, and found to his surprise that it led directly into the room again! He was back. "You are awake. Speak!" came the voice. Arcot shook himself, and looked about. A new voice spoke now, not the tonelessly melodious voice, but the voice of an individual, yet a mental voice. It was perfectly clear, and perfectly comprehensible. "We have traveled far to find you, and now we have business of the utmost import. Ask these others to let us treat them, for we must do what we can in the least possible time. I will explain when all can understand. I am Zezdon Fentes, First Student of Thought. He who sits on my right is Zezdon Afthen, and he beyond him, is Zezdon Inthel, of Physics and of Chemistry, respectively." And now Arcot spoke to his friends. "These men have something of the greatest importance to tell us, it seems. They want us all to hear, and they are in a hurry. The treatment isn't at all annoying. Try it. The man on the extreme right, as we face them, is Zezdon Fentes of Thought, Zezdon apparently meaning something like professor, or 'First Student of.' Those next him are Zezdon Afthen of Physics and Zezdon Inthel of Chemistry." Zezdon Afthen offered them the headsets, and in a moment everyone present was wearing one. The process of putting them _en rapport_ took very little time, and shortly all were able to communicate with ease. "Friends of Earth, we must tell our strange story quickly for the benefit of your world as well as ours, and others, too. We cannot so much as annoy. We are helpless to combat them. "Our world lies far out across the galaxy; even with incalculable velocity of the great swift thing that bore us, three long months have we traveled toward your distant worlds, hoping that at last the Invaders might meet their masters. "We landed on this roof because we examined mentally the knowledge of a pilot of one of your patrol ships. His mind told us that here we would find the three greatest students of Science of this Solar System. So it was here we came for help. "Our race has arisen," he continued, "as you have so surely determined from the race you call canines. It was artificially produced by the Ancient Masters when their hour of need had come. We have lost the great science of the Ancient Ones. But we have developed a different science, a science of the mind." "Dogs are far more psychic than are men. They would naturally tend to develop such a civilization," said Arcot judiciously. Chapter III A QUARTER OF A MILLION LIGHT YEARS