Time was when men had tried to label that binary, more than two centuries before, when it had first appeared. "Runaway Planet." "The Invader." "Rejoice in Messias, the Day Is at Hand." The labels were sense-free; they were Xs in an equation, signifying only that there was _something_ there which was unknown. "The Runaway Planet" stopped running when it closed on Earth. "The Invader" didn't invade; it merely sent down one slaggy, midnight-blue tetrahedron to Everest. And "Rejoice in Messias" stole Earth from its sun--with Earth's old moon, which it converted into a miniature sun of its own. That was the time when men were plentiful and strong--or thought they were--with many huge cities and countless powerful machines. It didn't matter. The new binary planet showed no interest in the cities or the machines. There was a plague of things like Eyes--dust-devils without dust, motionless air that suddenly tensed and quivered into lenticular shapes. They came with the planet and the Pyramid, so that there probably was some connection. But there was nothing to do about the Eyes. Striking at them was like striking at air--was the same thing, in fact. While the men and machines tried uselessly to do something about it, the new binary system--the stranger planet and Earth--began to move, accelerating very slowly. But accelerating. In a week, astronomers knew something was happening. In a month, the Moon sprang into flame and became a new sun--beginning to be needed, for already the parent Sol was visibly more distant, and in a few years it was only one other star among many. * * * * * When the little sun was burned to a clinker, they--whoever "they" were, for men saw only the one Pyramid--would hang a new one in the sky. It happened every five clock-years, more or less. It was the same old moon-turned-sun, but it burned out, and the fires needed to be rekindled. The first of these suns had looked down on an Earthly population of ten billion. As the sequence of suns waxed and waned, there were changes, climatic fluctuation, all but immeasurable differences in the quantity and kind of radiation from the new source. The changes were such that the forty-fifth such sun looked down on a shrinking human race that could not muster up a hundred million. A frustrated man drives inward; it is the same with a race. The hundred million that clung to existence were not the same as the bold, vital ten billion. The thing on Everest had, in its time, received many labels, too: The Devil, The Friend, The Beast, A Pseudo-living Entity of Quite Unknown Electrochemical Properties. All these labels were also Xs.