All the resources of the city had been hastily mobilized for defense. The entire population was enlisted; even young children served in the war industries plants that turned out synthetic food and munitions. For a time the population had been swelled by refugees from less fortunate localities, and even from the two smaller planets. But soon the city had been completely invested. And now a full half the defenders were already dead. * * * * * At last we were rescued from the tumult of our welcome by the harassed military commanders of the city. To a haggard, limping officer, Kel Aran repeated his anxious question: "Is there a girl of Earth in Achnor?" Emotion choked his voice. "Verel Erin is her name. A blue-eyed, yellow-haired girl, carrying the Dondara Stone--the diamond that is the life of mankind. Is Verel here?" The commandant shook a tired white head. "No," he said. "All the refugees who came to Achnor were registered. And there was none from Earth among them. I'm sure of that." The Earthman's unkempt yellow head sank. It rose again, stubbornly. "Please have your records searched again," he said grimly. "And use every means to find out if any man in the city knows anything of her--or any survivors of Earth. "Another thing!" he added suddenly. "Find out if any person knows the way to Malgarth's planet, Mystoon. She might be there." The officer shook his head again. "We'll try," he said. "But it will be no use to search the records. For if the Custodian were here, and free, she must already have offered us the power of the Stone. And no man has ever learned the way to Black Mystoon." Achnor was a city of magnificent ruins. Not one mile-high pylon had escaped some injury. The people were half famished, ragged, wild-eyed with fatigue and strain. But still they could sing. I heard them singing Kel Aran's old songs of the space-ways. And I was surprised to hear a Ballad of Barihorn--the lilting legend of my return to destroy the robots I had made a million years ago. That song depressed me bitterly. I realized more keenly than ever that I was a very ordinary man, hopelessly inadequate for that fantastic task. We were dining with the commandant, on scant bowls of a yellow flat-tasting synthetic soup, when appalling word came that the robots were breaking through the north defenses. A bomb had wrecked a power plant, opening a gap in the green shielding barrier of atomic energy. We followed the reserves rushed to meet the invaders. Never had I imagined anything so dreadful. The red gigantic ships, plunging out of the lurid smoky sky, rained tremendous bombs and slashed at the defenders with blue appalling swords of fire. Rocket batteries in the valley hurled ruin and death into the city. And a monstrous horde of robots, commanded by those graceful winged things of silver, came pouring through the gap. * * * * *