There were difficulties, of course. But Burl and Saya had the calm composure of savages, and the alertness of people who are changing the pattern of their lives of their own volition--and finding it very pleasant--and things went swimmingly. There was, on the spaceship, an "educator." They invited Burl to put it on his head. He obliged. And very shortly he understood a new language, and was equipped with a very considerable fund of general information. Among the items of information was the fact that presently he would have a splitting headache--he did--and that the making of records for an educator was so different that it required generations to get all the facts and knowledge for a single type of education down in permanent form. All of which fitted admirably into the arrangements that the men on the spaceship were anxious to make, and Burl was enthusiastically willing to accede to. He and his folk knew the creatures of the lowlands as nobody else could possibly know them. No electronic educator could possibly make a record making available that knowledge in less than two generations--maybe three. Therefore-- * * * * * The nightmare world swims in space about its nearby sun. It has a name now, but it does not matter. It has a city on it, which probably matters less. It is a curious city, though. The people in it wear gorgeous colored fur, and cloaks of butterfly wings. The least of the people in that city wear garments which would fetch fortunes on other inhabited worlds. In fact, such garments do. But it is most practical for Burl, and Saya, and their followers to wear such garments. There is no day but that a small, winged flying craft rises from the city to go silently over the plateau until it reaches the space above the cloud-bank, and then dives down into it. It is wise for the occupants and the operators of such small craft to wear garments like the other humans on this planet. They are recognized, that way, when garments such as most planets find suitable would make them seem strange. They want to be recognized, in the jungles and the noisesome valleys of the lowlands. There are other humans down there. The people of the city, of course, bring their fellows out as fast as they can find them. There is a session with an educator--and a splitting headache afterward--and very soon the folk who have hidden from monsters all their lives are zestfully hunting them with dogs. Presently they are hunting them with flying machines. It is a nice arrangement. The search for more people in the lowlands is a prosperous business even when it is unsuccessful. The wings of white morph butterflies bring the highest price, but even a common swallow-tail is riches enough. And the fur of caterpillars--duly processed--goes into the holds of the regular spaceliners with the same care given elsewhere to jewels and platinum.