 What isn't something that the aliens control?
Within the dome of the barrier, it looked more like a well-kept if bizarre little country estate. 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. Eudalia had been a female foreman in a garment-cutting shop before being captured and brought through. It arrived before the meal, materializing against one of the seven walls of the roofless chamber. Somehow it brings things closer...." This was so with all of their foods, with their cigarettes, with everything in their prison—or their cage. Their captors were utterly without a human conception of smell, living, apparently, in a world without odor at all.
 how the captives feel about being there
 how the captives feel about being there  what the captives eat  the captives' desires  where the captives live