"You came in search of us--you came through space just to find and rescue us!" Haldgren, it seemed, could not recover from the effects of this unbelievable fact. He was gripping hard at the hand of Chet Bullard, while his other great arm was thrown about the shoulders of Spud O'Malley. "But now that you are here, what is to be done? Every exit will be guarded; we are shut off from the outer world by a hundred locked doors and by thousands of those beasts." He took his arm from Spud's shoulder to point toward the great doors, beyond which was a rising clamor of shrill sound. "They will break in here soon; they would have been here before had they known of the old lost entrance of the priests that Anita and I found. We're as bad off as ever, I am afraid. There will be no holding them now." "I can hold some," said Chet, and touched his weapon. Haldgren nodded his shaggy head. "Some, but not many of the thousands we must face before ever we fight our way through to the outer world. No, my friend Bullard, that will never save us; we are doomed!" But Chet, unwilling to accept or share the other's convictions, was seeing again the great room beyond those doors--a room of vast proportions; of high-arched, vaulted ceiling where sweeping curves all centered and ended in one tremendous central point. It hung down, that point, a blazing pendant--an inverted keystone; through some magic of that ancient people all the colors of the spectrum had been made to ebb and flow like rainbows of living light. * * * * * But something deeper than the beauty of this had impressed Chet. A master pilot does not study design of structures, even structures meant for travel through the air, without gaining knowledge of architectural fundamentals; his mind, subconsciously, had been following strains and stresses through those super-imposed curves. He turned abruptly to Haldgren with a question. "It seemed to me when I was following Anita that we climbed upward; we were always running upward through the passages. We must be near the surface of the Moon; is that true?" Haldgren nodded slowly. "I think so--yes! In the great room out there are windows of quartz high in the ceiling. You could not see them from where you were, but they are there. I have seen them lighted; I think it was the light of the sun." "In that case," said Chet quietly, "I will ask you to open those doors." "But they will come in!" the big man protested. "They will not come in." Chet turned to the girl. "I will ask you, my dear, to accompany me--if you have faith." And, to that, Anita Haldgren granted not even a word of reply. She moved more swiftly than her brother to a controlling lever in the wall ... and the ponderous doors swung slowly back. * * * * *