The words dripped into Allan's consciousness. Beyond them, he could hear movements, exclamations. But they meant nothing to him. Only the one thought tolled, knell-like, within him. "We seven are the only living humans left on Earth." * * * * * Dimly he knew that Anthony was talking. "There is a possibility, a bare possibility, that somewhere near here there are two others. That chance is faint indeed. Otherwise humanity is dead, killed by its own hand." Through a dizzy vertigo that blurred sight and sound Allan heard the rounded voice go on and on, telling the story of the doom that Man's own folly had brought. And intermingled with that tale of a world gone mad there came back to the listener the clear-cut vision of the day of horror that to him seemed but yesterday. He remembered the sudden ultimatum of the Easterner's, the Western Coalition's stanch defiance. Again he saw a supposedly invincible fleet utterly destroyed, saw comrades whiffed out of existence in infinitesimal seconds. Again he watched a city of twenty millions inundated by a muddy yellow gas in which no human being, no animal, might live. He waked once more to find himself helpless with weakness, among living corpses, in a place that seemed a tomb. "All this we saw in our long-distance televisoscope." Anthony gestured to a blank screen above the apparatus ranged along the opposite wall. "Then, just as that last weird battle ended, something happened to the eye-mast outside, and we were isolated." He fell silent, in a brooding reverie, and Allan, recovered somewhat, saw that the other strange occupants of the place had risen and were clustered about that cage where something fluttered. He turned to his mentor. "But I still don't understand. How is it that we escaped the holocaust?" "Four of us, members of the scientific faculty of the National University, having foreseen the inevitable result of the course of world events, had joined forces and developed a substance--we called it nullite--so dense and so inert that no gas could penetrate it or chemical break it down. We offered it to the Western General Staff, and were laughed at for our pains. Then we decided to use it to preserve our families from the danger we foresaw. "At first we sheathed one room in each of our own dwellings with the nullite. Later we decided that the deposited gas might last for many years, and blasted out this cave, a hundred feet below the summit of Sugar Loaf Mountain, for a common refuge.