Many terrifying ecological disasters threaten the earth. But it would take an intense psychological shock to get people to make a serious effort to brief themselves on such problems by contacting the few competent people in this field, whose voices are submerged in media noises. But this psychological shock hits Mr. And Mrs. Poitevin, in an odd way. They have some very old friends, the Moranes—simple, ordinary people, like everybody else. But one evening, these friends announce they are leaving, for good. Where are they going? Back to their planet! They are extraterrestrial beings, and they were checking out living conditions on earth. But our planet has become too dangerous, and it’s all washed up. The Moranes have received orders to leave it at once. The Poilevins can’t believe their ears, but once their friends have left, they make their own investigation. What they learn about the earth’s future is so frightening that they, in turn, decide to flee from the earth.