It began with the sighting of the Scorpion ships in the new 400-inch reflecting telescope on Mount Palomar. The ships landed on Earth to disgorge aliens quite indistinguishable from human beings, except that they were all apparently equal to the genius level of human beings. And, all were in perfect physical condition. They came in peace, they said. Their leader spoke to a plenary session of the United Nations — nations truly united now in the face of what might be a threat to all the peoples of Earth — and he talked as if he were talking to old and trusted friends. He said, "You have asked for proof that we are a responsible and enlightened race. There can be no wisdom without strength, no true enlightenment unless the power to work immense harm exists and is deliberately renounced. We have come to Earth on a scientific mission only, just as someday you will travel to the stars. We ask only complete freedom... your friendship, trust, and understanding as long as we choose to remain." He said that the Scorpions abhorred any form of aggressive violence directed against a fellow human being, or a nation, or an entire planet. He offered to give the peoples of Earth a demonstration of Scorpion power. An island was selected for the demonstration, and at the time appointed, all the peoples of Earth saw that the Scorpions had neither lied nor exaggerated; when the moment came, a single Scorpion spaceship hovering over the island seemed to shudder along its entire length. Then a blinding burst of incandescence came from it, sweeping downward and outward until the entire island was enveloped in a bright, steady glow. When the glow vanished, the island was gone. Yes, the Scorpions had the power to conquer or destroy Earth, but after seven years, no one knew as yet what their "scientific mission" was, how long they would stay, or what their relationship with Earthlings really meant. Even though there had never been even a hint of interference with the governments of Earth, people felt as if they were in the presence of benevolent dictators, gradually imposing a control upon them. Then a man strayed too close to the single Scorpion ship that had been damaged in its landing upon Earth, a ship which had been open to all visitors as an exhibit, then suddenly declared off-limits. What happened to this man, no one could tell. He was found wandering in a swamp, in a peculiar state of amnesia. All general knowledge he had, he retained — but of personal knowledge, who he was, what his life and contacts had been, there remained no trace. He spoke of "glory" and seemed afraid that those who were trying to help him find himself, and find out what had happened to him, would steal something infinitely precious from him. Hypnosis brought back his missing memories; and with them came overpowering terror. Jim Lawrence was a native of the Vermont town where Gillings had had his experience. He was selected to investigate a job that seemed hopeless, for no one had been able to discover anything more about the Scorpions than they had volunteered about themselves. Here is a gripping novel of a strange and wonderful people and the horror that was destroying a wonderful civilization. A group of Earth-people's mission to a star was to save a superior race which could not heal its own sickness.