Later that evening, dancing, they covered their wariness carefully. They might be under observation in any of a hundred different ways: by probe beams, hidden cameras, or by individuals, android or human, whom they did not know. In spite of old loyalty, Ed Dukas was not entirely at ease with the thought of contacting Mitchell Prell. Yet, he wished to avoid being trailed so that he could act alone and separate from the dictatorial and often panic-stricken opinions of others. On Mars there had been considerable violence, too, though there had been no gliding, sinuous things that brought nocturnal terror. But here, too, there was a mingling of android and human being, with no visible marks to distinguish the one from the other, though to many the difference was as great as that between man and werewolf. Barbara seemed to grow sleepy in Ed's arms as they danced. Ed yawned slightly. So they drifted from the room and back to their own quarters. Ed pulled the old envelope from the pocket of the coat on the chair. As he had hoped, a message was traced waveringly on it: "_Go Port Karnak--then E.S.E. into desert._" Both Ed and his wife knew that Martian deserts surpassed all earthly conceptions of desolation. They looked at each other. The challenge was still in Barbara's eyes. The fact that she could carry a pack was a matter that had been settled long ago. Now Ed risked speaking--in the lowest of audible whispers: "So, instead of going to bed, as people in our position should, we start traveling--fast." He felt the safety pouch under his belt. Personal recordings were in it: tiny cylinders, a pair for each of them. A precaution. In the vaults on Earth there should still be others. But one could not always be sure of those. Some had disappeared. As memory of what he thought he had seen in a tiny ink drop still clutched rather frighteningly at Ed Dukas's brain. It was a hint of how Mitchell Prell wrote his messages--in an utterly simple and heroic way, but with fantastic, dream-shot implications. Could it be part of android flexibility? Well, probably his fancy had tricked him, because things couldn't be that odd. Still.... Often Ed had felt bitter over the confusions created by the advance of science. But now enigmas led him on as thrillingly as ever. There had to be wonders ahead, for thinking of Mitchell Prell without thinking of new science was impossible. "Let's go, Babs," he whispered. Casually, like ordinary guests checking out, they put two light valises into the conveyer and dropped to the main floor by elevator. The rest of their stuff they left behind. They paid their bill and took an auto cab to the central tube station. In the washrooms they changed from leisure clothes to the rough gear used in the Martian wilderness: light-weight vacuum armor and oxygen helmets equipped with air purifiers and small radios--all fitted over light trousers and shirts. The remaining contents of their discarded valises they transferred to rucksacks.