There was no effective defense against them. Now and then one of their air ships was shot down but invariably it exploded before crashing. At last, in desperation, the United Governments had attempted to get operatives through with the captured persons. Ostby was one of the few instances of success. For six months now, by dint of adroit maneuvering and luck, he had managed to stay alive, but he was no nearer to closing the "door." Impatiently Ostby climbed to his feet and began pacing the room. He had never been able to get used to these rooms, with no corners, and all their furniture in the center. But they made for convenient pacing. Had he been wrong in his estimate of the Duchess, he wondered. She had appeared too much woman to let matters of the state come ahead of her private affairs. Suddenly he stopped in mid-stride as there came a gentle tapping on his door. He had not been wrong! II The Duchess had been a woman of her word, Ostby reflected, as he leaned against the counter sipping his drink. Knowing full well who he was, she had allowed him to leave, making no demands of him, and inviting him back whenever he cared to come. She was quite a woman. Some day, if and when he was able to clear up this business, he would return. Now the time had come for him to change tactics. He had been able to accomplish nothing by playing a lone hand. He needed help. When you opposed the police the best place to seek help--he had decided--was among others who broke the law. Thus he returned to the Flats, hangout of the underworld. To make his contact with the underworld the first step should be some spectacular move that would focus their attention on him. "Fill it up," he said, sliding his glass along the bar. From his pocket he drew a thick roll of bills, a thickness caused by paper padding. He paid for his drink and laid the roll carelessly at his elbow. A minute went by and he felt someone slide in beside him. From the corner of his eye Ostby observed his companion. When he saw a hand close over the bills, he reached swiftly over and gripped the wrist of the hand that held the money. "Drop it," he said. The thief's lips parted over stained teeth, but he said nothing. For a moment he stared back, viciously, then he shifted his body slightly and Ostby felt a knife point pierce the flesh of his right side and come to rest against his ribs. "Let go, bud." The thief spoke low without moving his lips. Ostby hunched his shoulders and twisted his body around in a half circle. As the thug went off balance Ostby pulled forward, still gripping the wrist, and threw him over his shoulder. The thug struck the floor on the flat of his back, and the wind left his lungs. He lay for a moment, his body doubled up, and one leg kicking spasmodically, as he fought for breath. Ostby bent over, picked up his money, and leaned backward, with his elbows resting against the bar, and watched the struggling man.