 What is the central theme of the story?
They entered the house, which had no roof, continued to move beneath a sky that glowed with light which did not come from a sun or moon. It arrived before the meal, materializing against one of the seven walls of the roofless chamber. Somehow it brings things closer...." We seem to be in a universe of different properties as well as different dimensions. "They pass through their gateway to Earth at considerable danger and, probably, expense of some kind. "In the one instance, we're the hunters, the breeders, the trophy collectors. As in all of this strange universe, excepting the dome-cages in which the captives were held, the training hall followed no rules of three-dimensional space.
 Experimenting with living creatures -- regardless if it is for entertainment or research -- is unethical, and humans may one day find themselves as subjects.
 In undesirable circumstances, it is best to remain guarded on the inside, but to display an agreeable, obedient, and non-threatening countenance.  Be careful what you worship -- be it vanity, reputation, or money -- because if you make it the center of your world, you will always feel inadequate.  All relationships are ultimately temporal due to three dimensional time and space -- it is only through the fourth dimension that true love can be achieved.  Experimenting with living creatures -- regardless if it is for entertainment or research -- is unethical, and humans may one day find themselves as subjects.