"They have it all right," said Orth, scowling down at the open parklike meadow toward which Horn was blasting, "but I'm worried about getting back. So far this time travel is simply negation--outside the _Time Bubble_ three million years pass and to us it seems less than two hours." Horn thrummed the landing jets smoothly and laughed his deep booming bellow. The grassy glade came up to meet them. "A minor detail," he said as he cut the jets and the ship jolted abruptly to an uneven grounding. The deck was slightly tilted and from below there sounded a muffled explosion. "You all right, Neilson?" shouted Orth into the intercom. The third member of their crew sounded breathless as he answered from the power compartment. "Thought the mixer was going for a bit," he gasped. "A forward jet went kafoo. Boulder maybe blocking off that last blast." Orth told Horn what Neilson had said. The big man unzipped his safety harness and came over to his side, his big capable hand on Orth's shoulder. "Don't worry about getting home," he said, taking up the thread of conversation the explosion had disrupted. "In three million years all the secrets of time and matter will have been discovered. We'll return with the shield." He released the young scientist's bruised shoulder and slapped a great paw of a hand on his back, pushing him down toward the airlock. "Better replace that jet tip, Devin," he said. "Can't tell but we may have to take off in a hurry. This future civilization might be unfriendly and," he paused thoughtfully, "even non-humanoid." Orth checked the gauges at the lock and found the outer atmosphere to be a heady oxygen-rich mixture. Horn had gone down to help Neilson in the power compartment and he was alone. He stuffed the jet tip into his bag of tools and pushed through the inner port into the airlock. There he snapped on the invisible, but oddly tingling, radiations that would destroy any alien spores of deadly growth that might find their way into the ship. He swung open the thick oval outer door and dropped the short grounding ladder to the blast-blackened turf. Down the eight rigid metal rungs of the ladder he went to the ground. He stumbled awkwardly and almost fell. The unaccustomed gravity, after the past twelve days in space--twelve days that had actually been thirty thousand centuries--had tricked him. A moment later his muscles had quickly remedied this unbalance and he found the fused jet that had blown back. As Neilson had guessed, the _Time Bubble_ had grazed a boulder in landing and the expanding rocket gases' escape had been blocked off. It was good to feel the spring of turf underfoot. Even the feeble warmth of the ancient sun was pleasant on his bared flesh. He had not realized how homesick he had grown for Earth until now.