Sylva peered anxiously at him from behind a huge boulder. He raced toward her, expecting every second to hear the spitting of Kreynborg's pocket-gun. With the continuous-fire stud down, the little gun would shoot itself empty in forty-five seconds, during which time Kreynborg could play it upon him like a hose that spouted death. But Thorn had done the hundred yards in eleven seconds, years before. He bettered his record now. The first of the little green flashes came when he was no more than ten yards from the boulder which sheltered Sylva. The tiny pellet had missed him by inches. Three more, and he was safe from pursuit. "But we've got to get away!" he panted. "He can shoot gas here and get us again! He can cover four hundred yards with gas, and more than that with guns." They fled down a tiny water-course, midget figures in an infinity of earth and sky, scurrying frenziedly from a red slug-like thing that lay askew in a mountain valley. Far away and high above hung the war-planes of the United Nations. Big ones and little ones, hovering in hundreds about the outside of the dome of force they could neither penetrate nor understand. A quarter of a mile. Half a mile. There was no sign from Kreynborg or the rocket-ship. Thorn panted. "He can't reach us with gas, now, and it looks like he doesn't dare use a gun. They'd know he wasn't a Martian. At night he'll use that helicopter, though. If we can only make those ships see us...." * * * * * They toiled on. The sun was already slanting down toward the western sky. At four--by the sun--Thorn could point to a huge air-dreadnaught hanging by lazily revolving gyros barely two miles away. He waved wildly, frantically, but the big ship drifted on, unseeing. The Fighting Force was no longer looking for Thorn and Sylva. They had been carried into the rocket-ship fourteen hours and more before. Sylva's screaming had been broadcast with the weird hoots and whistles the United Nations believed to be the language of inter-planetary invaders. The United Nations believed them dead. Now a watch was being kept on the rocket-ship, to be sure, but it was becoming a matter-of-fact sort of vigilance, pending the arrival of the rest of the Fighting Force and the cracking of the dome of force by the scientists who worked on it night and day. On level ground, Thorn and Sylva would have reached the edge of the dome in an hour. Here they had to climb up steep hillsides and down precipitous slopes. Four times they halted to make frantic efforts to attract the attention of some nearby ship. It was six when they came upon the rim. There was no indication of its existence save that three hundred yards from them boughs waved and leaves quivered in a breeze. Inside the dome the air was utterly still. "There it is!" panted Thorn.