Quickly, Dynamon turned and faced the men behind him and held up his hands in a gesture signifying that no one should use his radio phone. He had determined to try and help his beleaguered soldiers down in the valley, and the only way that could successfully be done was to surprise-attack swiftly on the rear of the Martians. He motioned Keltry and Thamon back into the pit and then, sweeping his arm forward in a wide arc, he plunged down the hillside. But before he had covered half the distance to the combat in the valley, Dynamon realized that his attack was coming too late. The Photo-Atomic Ray was cutting down the little force of humans like an invisible scythe. There were only nine of them left now and one by one these were falling. A thousand thoughts raced through Dynamon's head. Should he go ahead with the attack, courting on getting within bombing distance of the Martians unnoticed, before they could swing their Photo-Atomic Ray around? Or, should he change direction, skirting the enemy, and make a run for the Carrier? Suddenly, his blood froze in his veins as a voice sounded in his ear phones. "This is suicide, Dynamon!" It was Mortoch's voice. "It's suicide now!" said Dynamon through clenched teeth. "You fool! You have given us away!" There was an instant reaction from the swarming Martians in the valley. A large group of them broke away from the combat and rolled over the gray sand toward Dynamon's detachment. The centurion halted his men abruptly. It was sure annihilation to try and stand in the face of the oncoming men of Mars. "Back to the pit!" Dynamon commanded. "It's our only chance. Once we get down there we'll decide what to do later." The little force just barely made it to the mouth of the shaft. The Martians were coming up rapidly behind them, and Dynamon could see the big, black cones which produced the invisible Ray. * * * * * The descent down the shaft was rapid, Dynamon being the last to land on the shiny floor. Immediately, he marched his men through the passageway into the Nether World and detailed two men to remain and guard the entrance to the pit. "I don't believe the Martians will follow us down," he said. "If they do, we can easily defend the passageway." Then he turned and singled out the Chief Decurion. "Mortoch," he announced, "you are under arrest. You disobeyed my orders in regard to using the radio phone, and by doing so you betrayed our presence to the enemy. I will dispose of your case later." Mortoch stepped forward, a sardonic gleam in his dark eyes. "And suppose I refuse to be arrested?" he said. "If I had not disobeyed the order, you would have led us into certain death." Mortoch swept the crowd of soldiers with a burning look. "Men, I proclaim that Dynamon is incompetent to command you. Henceforth, you will take your orders from me--and _you_, Dynamon, are the one who is under arrest." "Mortoch!" Dynamon cried. "You are out of your mind!"