Down the street we ran, careless now of any that might hear, until there loomed at its end before and above us the vast box-like building of the rulers. None of the creatures of darkness could be seen around it, and we sprang toward the great square open door, then halted for an instant despite ourselves.
Far away across the city was sounding a humming as of a gigantic swarm of bees. It was a sound that I knew well and one that drove the blood from my heart. It was the sound of the generators of great space-ships throbbing, and as it sounded there was lifting over the city a mass of hundreds of the gleaming ships!
Away to our right another mass of equal size was rising, and far behind us in the strange city another, and still others at a greater distance from us, thousands of huge interstellar ships loaded with all the eyeless hordes! They were starting out from their world and from the cloud on their career of dread conquest!
"They're starting!" I cried to Zat Zanat. "We're too late!"
"Not yet!" he cried. "Look, there's still a ship waiting on the roof! They must be slaying their prisoners now!"
For on the roof of the great building before us we glimpsed a waiting cruiser that had not yet risen. The significance of it and of Zat Zanat's cry drove home to my brain at the same instant. It was waiting for those in the building, those who were killing the prisoners they had kept there. And Jhul Din and Korus Kan-!
I uttered a cry of rage, leapt forward and through the door with Zat Zanat close behind me. I vaguely glimpsed great halls through which we raced, queer seats and desks and instruments, and then with my companion beside me was leaping up the broad flight of curving steps ahead.
Up it and up another stair we raced, and then my face blanched and I threw myself on at greater speed as from somewhere in the great building over us came shriek on shriek of the most dreadful agony, ending in each case in quick silence but taken up at once by other voices.
"The pain-producers!" Zat Zanat sobbed. "They're slaying the prisoners with them!"
"Jhul Din! Korus Kan!" I cried, madly, and then cried out again as there came to me from above somewhere a faint answering shout. We rushed up into the next level, along a broad corridor, and halted before a solid door from behind which came the cries of my friends.