A red light bulb flashed on the wall, and then, without waiting for permission, a Space Man rushed into the room, his arms waving wildly, forming frantic signs of the Star People's deaf mute language. Bent in a half crouch, his great arms flexed, Ankova translated for the benefit of the Earthians: "Fourth World Man escape--in _Selba_. We are betrayed--someone help him. He out of sight already. Going to help Black Emperor. And now red star burns in space--spy's warning--Alkebar forces start!" Telaba rushed to a big lever and pulled it. Immediately a huge trip hammer began to pound ponderously on a metal plate set in the ground outside the building--sending vibrating pulsations out through the crust of the planetoid--the alarm signal which would be sensed by everyone of Telaba's men, telling them to be ready for instant action. The four looked at one another. Each knew what this last move of the Prince of Selba meant, but no one thought for a moment of giving up the fight. "It won't do any good to pursue the Martian," Shelby cried. "That ray projector of his--he'd blast us out of existence. All we can do is try to hinder Alkebar's invasion--seek to delay him. If I could only somehow get through to Mars with the secret of the Atomic Ray! Telaba, haven't you a ship capable of carrying a large enough oxygen supply to last me for the journey?" "Never mind!" Ankova cut in. "I go! Many times I been to Mars. Give me plans. I go right away. I get them to fight." Shelby drew from his sleeve pocket the black case containing information concerning the Atomic Ray which he had recovered from Hekalu Selba at the time of the Martian's capture. He opened it, and with his stylus added a brief message to the mass of notes inside, and wrote down the formula for a certain complex chemical compound. Then he handed the case to the Space Man. "Take it to Alman Mak in the Checkald of Taboor if you can, Ankova. Good luck." The son of the rebel chief hurried from the room with the missive in his hand. Shelby knew in his heart that to attempt to get Earth and Mars into action in time was a useless gesture, but he could not suppress a thrill of admiration for this wild son of the void. There was hard mettle in Ankova's makeup, hard and true. And most of them were like that--most of Telaba's men anyway. "You two come with me," Telaba was saying. "We fight together. Put on space suits." He was tapping an instrument resembling a telegraph key. In unison with his movements the heavy signaling hammer sounded out orders and commands to his forces. * * * * *