"Very well, Borisu!" cried the engineer, his voice changing suddenly. "I _will_ do something!" His hand leaped out and tore the pistol from the _kraedar's_ grasp, in one split second completely changing the situation. "Down on your face, and keep your arms outstretched above your head! Tell your men to throw their weapons away." CHAPTER XX The Last Treachery "Kang!" The name burst from Lark O'Day's lips. "Quickly!" crisped the Martian scientist. "Pick up their guns! Daughter--" As Lark and Gary and Nora scrambled to the task of collecting the astonished Magogeans' fallen weapons, Kang directed his attention to Penny--"you will find my former slave apparel in that cupboard. Tear it to strips and bind our enemy." "Bind him?" demanded Lark. "Why waste good rags on a scoundrel like that? I know a better way to take care of--" "No!" commanded Dr. Kang. "We will need him to transmit our peace terms to the Magogeans when our allies have flooded the city." "And these others?" Kang said, "The storage closet over there. Throw them into it and lock the door. There is no reason to occasion useless bloodshed. These soldiers have committed no crime but that of obeying orders." "Okay," said Lark. "You're running the show." He herded together the now helpless and sadly bewildered half dozen Magogean guards, and thrust them into the cubicle pointed out by the scientist. When the door was secured behind them-- "But how did you manage to get control of this chamber?" asked Nora Powell. Kang shrugged. "It was very simple. There was but one man watching these panels when I was brought here: the technician whose garments I wear. He expected no trouble from an elderly slave. And since we two were alone--well, it seemed an elementary precaution to don his clothes before I began the necessary operations." "And the barrier?" inquired Gary eagerly. "You have lifted it yet?" "Not yet. I had first to make a few alterations in the Magogean machinery. I wanted to make sure a power failure would not cause the barrier to fall before all our allies had entered. My work is now complete. And so--" Kang turned to the panels. His hands tugged at a single gigantic switch. No light glowed. There came no change in the humming sound that permeated the control room. The adventurers looked at Kang and at each other anxiously. Penny spoke for all when she asked, "You are sure, O my father, that the barrier is open?" Kang said, "See for yourself." And he pressed a stud which lighted a vision screen before them. What they saw left little doubt as to the effectiveness of Kang's accomplishment. For the screen reflected one segment of the imperial city's surrounding wall, a location which had been a gate in Khundru's defenses. But now that sentry post existed no more. It was a mass of broken kindling trampled under the rushing feet of hordes of Gogeans who had burst from their place of ambush to storm the city.