[Footnote 4: Tugh had been in the Power House before. He knew the operations of its various controls. But he had come always by the surface route; he had heard of the existence of the secret tunnel, but had never before this night been able to find out where it was.] "You stay here," I told Tina and Larry; "I'll go up there. I'll get him now once and for all." * * * * * I reached the Power House roof. The storm tore at me. It was beginning to rain. I was near the outer edge of the roof, and ten feet away stood the oval tower. I saw windows twenty feet up, with dim lights in them. Mingled with the storm was the hiss of the transmitter in the top of the tower, and the roar of Tugh's magnified voice. He had evidently been there only a brief time. From where I crouched on the roof, I could see overhead, along the top edge of the dam looming above me. The red Robot rays were everywhere in the city, but none as yet showed along the dam's upper roadway. I got into the tower and mounted its small stairs. Creeping cautiously to the entrance of the control room, I saw a fairly large, dimly lighted oval apartment. Great banks of levers stood around it; tables of control apparatus; rows of dials, illumined by tiny lights like staring eyes. There was another gruesome heap of garments here on the floor; a grinning white skull leered at me. This was the main control room of the Power House. Across it, near an open window, Tugh sat with his back to me, bent over a table with the grid of a microphone before him. I raised my cylinder; then lowered it, for I had only a partial view of him: a huge transformer stood like a barrier between us. * * * * * Noiselessly I stepped over the threshold, and to one side within the room. The place was a buzz and hiss of sound topped by Tugh's broadcast voice and the roar of the storm outside--yet he was instantly aware of me! His voice in the microphone abruptly stopped; he rose and with an incredibly swift motion whirled and flung at me a heavy metal weight which had been lying on the table by his hand. The missile struck my outstretched weapon just as I was aiming it to fire, and the cylinder, undischarged, was knocked from my hand and went spinning across the floor several feet away from me. Tugh, like an uncoiling spring, still with one continuous motion, made a leap sidewise to where his own weapon was lying on a bench, and I saw he would reach it before I could retrieve mine. I flung my heavy battery box but missed him. And as I rushed at him he caught up his cylinder and fired it full at me! But no flash came: only a click. He had exhausted its charge when he killed the Power House guards. With a curse he flung it at my face, and my arm took its blow just as I struck him. We fell gripping each other, and rolled on the floor. I was aware that Larry and Tina had followed me up. Larry shouted, "Look out for him, George!"