The last aero-sub took to the sky, and the Americans rushed into battle with fine disregard for what they knew must be certain death. They were not fools, exactly, and they had seen, but not understood, the manner in which those gallant old hounds of the sea had been erased from existence. But in they went, plunging squarely into the heart of the aero-subs' leading formation, which formation consisted of three aero-subs, flying a wing and wing formation. The young American signaled with upraised hand, and the American pilots made their first move. Every plane started rolling, at dazzling speed, on the axis of its fuselage, while bullets spewed from the guns that fired through the propellers. Bullets smashed into the leading aero-subs, with no apparent effect, though for a second it seemed that the central aero-sub of the leading formation hesitated for a moment in flight. Then, swift as had that black streak flashed from the nose of aero-subs submerged, a streak darted from the nose of the central aero-sub, and glistened in the sun like molten gold! * * * * * It touched the youngster who had called for volunteers for his attack against this strange enemy. It touched his plane--and the plane vanished instantly, while for a fraction of a second the pilot was visible in his place, in the posture of sitting, hand on a row of buttons which did not exist, head forward slightly as he aimed guns that had vanished. Then the pilot, still living, apparently unhurt, plunged down eight thousand feet to the sea. The water geysered up as he struck, then closed over the spot, and the gallant American youngster had become the first victim in battle of the monsters of Moyen. Victim of a slender lancet of what seemed to be golden lightning. "He could have killed the pilot aloft there," came quietly from Munson, "but he chose to pull his plane away from around him! Their control of the ray is miraculous!" As though to confirm the statement of Munson, the leading aero-sub struck again, a second plane. The plane vanished, but from the spot where it had flown, not even a bit of metal or of man sufficiently large to be seen by the delicate recording instruments of Maniel dropped out of the sky. The ray of gold was a ray of oblivion if the minions of Moyen willed. CHAPTER VIII _Charmion_ "Prester Kleig," came suddenly into the Secret Room the voice of far distant Moyen, "you will at once make a change in your rules regarding the admission of other than Secret Agents to the Secret Room. You will at once see that Charmion Kane, sister of your friend, is allowed to enter!" "God Almighty!" A cry of agony from the lips of Prester Kleig. He had not forgotten Charmion, but simply had had to move so swiftly that he had put her out of his mind. For a year he had not seen her, and an hour or two more could not matter greatly.