"How can it be removed? There is a way, my son, a dangerous, almost impossible way, but one which I have spent my entire life planning. The space warp has been devised to have seven focal points, lying along the plane of the seven cities. I have devised transmitting equipment which will discharge a beam along this plane, thus nullifying the space warp. But, to accomplish this, entrance must be made into each of the seven cities, and that would mean contracting the terrible plague in not one but all seven of its virulent forms. "I have taken care of that too. I have compounded a pellet which will give temporary immunity to the plague if taken at the proper intervals and...." Here Hol-Dai's mind gave way again, and he lapsed into unintelligible babbling. I mulled over this story for a week. During that time I read over Hol-Dai's case history and discovered that his lucid intervals were fairly intermittent and complete. That is, when he was normal, he remained so until he lost his grip entirely. Next I visited the place where he had lived before he was confined to the hospital. My credentials gained me entrance and the right to go through his possessions. Nothing had been touched. I found his vial of immunity pellets with full instructions as to dosage. And I found in his equipment the seven miniature transmitting sets and the necessary connecting wire. In his papers, however, I searched in vain for reference to the Jupiter Stone. But I didn't stop there. I haunted public libraries and the archives-galleries, always seeking proof for everything Hol-Dai had told me. Where I didn't always find proof, I found "possibility." The old man's story could be true. As I read over the history of Ganymede, the lure, the fascination of that "stone" swept over me. It became a narcotic, off-setting all other desires until I knew I must act. I took Hol-Dai's equipment and his vial of pellets, and I spent one week studying the geographical layouts of the seven cities. I drove in a tracto-car to the first city of Profaldo, and as you have seen, I successfully "planted" the first transmitting set. "One down, six to go," I told myself grimly. Full confidence was mine, and my spirits were riding high. <tb> Senar, the second city, came out of the haze abruptly. High in the sky the immense disc of Jupiter cast a reddish light over the metropolis. As before, all roads leading across the flat converged on a single runway, leading to the main gate. I entered, and it seemed time had turned backward, erasing the intervening hours. For Senar was the same as Profaldo. The same roaring drink shops and crowd-choked gambling casinos. The same twisting despondent streets sunk in filth and mockery of the law. Again I came to the building marked POWER DIVISION. In the Commissioner's office, however, I was due for a surprise. A girl turned to me inquiringly. She was tall, svelte and dark-haired, with agate eyes that bored me through and through. "Well?" she said.