 What didn't Roger learn when he returned to Earth?
It arrived before the meal, materializing against one of the seven walls of the roofless chamber. "They pass through their gateway to Earth at considerable danger and, probably, expense of some kind. He had felt the inner tug of command, said good-by to the women and returned to his smaller compound within its own barrier dome. It didn't actually look like anything save some half-nourished dream a surrealist might have discarded as too nightmarish for belief. 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.
 that he could stay if he used his new powers
 that the aliens couldn't capture other men  that he had been in a car accident  that his wife had found someone new  that he could stay if he used his new powers