"Turn it off!" bellowed the man in the heat suit. But it was already working. The prismatic flare on the screen showed no vision impulses were coming in, showed that whoever was calling was using a sound transmitter only--a portable set like those in a heat suit. A voice said sharply: "Attention, Junta! The man who claims to be the Chief is a masquerader. Kill him! This is the Chief speaking now!" V Doubt sprang into the eyes of every man present. It lasted only a second--for the masquerader's action proved the charge against him. He grappled the pyro from dazed Vincennes, sprang back, fired a warning blast that smashed the telescreen. "Don't move, anybody!" he ordered. "Nolan--take their guns!" Nolan threw questions to the winds, sped to obey. He found a business-like little heat pencil in the inner pockets of the chunky man, a pearl-handled burlesque of the service pyro in the gaudy gemmed holster Lieutenant Brie dangled from his belt. Nothing else--and his search was thorough. "All set," he reported. "Good enough. Searle--are there heat suits in this room?" The chunky man looked stricken. He nodded. "In that locker," he said dizzily, pointing to the wall. "Get them out, Nolan. Give one to every man and put one on yourself. Those outside will take their chances." Nolan raced to comply. The stillness outside the door was menacing. While he was dragging the suits out, throwing them at the men, while they were putting them on, the man called Searle was staring at the masquerader with dawning comprehension. "What are you going to do?" he whispered. "Are you--" The man in the heat suit laughed sharply. "Get your suit on," he said. "You know what I'm going to do. All set?" Every man was garbed, helmets down. "Ten seconds to seal them. One, two, three--" He counted slowly and Nolan watched him with fascination. At _five_ the gauntleted left hand came up to the butt of the pyro, worked the tiny chambering lever half a dozen times. Nolan gasped in spite of himself. There were seven lethal pyro charges in the chamber of that gun--enough to blast down a mountain! The count was finished. Through Nolan's helmet radio, automatically turned on, the man's calm voice ordered, "All right, Nolan. Open the door and let them in!" Nolan moved. As his hand was on the lock, just as it turned and the door swung loosely inward-- _Blam!_ the impostor swung and fired the massive charge in his pyro at the thin wall that kept air and life in the dome! They were running over icy ground. At most there was a minute or so of advantage--less, if the men they'd left in the room had other weapons concealed somewhere. And still Nolan didn't know who his savior was. "All right, now," he panted over the helmet phone. "Give. Who are you?" The answer was a chuckle, mixed with gasping as the smaller man strove to match his speed. "Tell you later," he panted.