Stanley spoke with conviction, but he had no way of knowing what the future had in store for him. Just as the past years had brought the momentous events due to the World War, so there had been events of importance in the Hidden Valley, also. If Ted and Stanley could in some manner have obtained an inkling of what had happened behind those silent and unscalable mountains that surrounded the retreat of the last of the Incas, they doubtless should have refrained from making another attempt to secure the fabulous wealth that this same barrier also protected. Firmly resolved though they were not to enter the Hidden Valley proper again, it was not impossible that circumstances beyond their control might take them into the very region they were so eager to shun. And then--the terrible reckoning, with the pitiless, triumphant, and all-powerful Quizquiz as their captor and judge. They landed in Mollendo just in time to take the early afternoon train into the mountains, and night found them in the upland city of Arequipa. It required the greater part of another day to cover the distance to Puno, and on the morning after that the journey to Cuzco began. As the train crept wearily over the high plateau and entered the outskirts of the city, Ted, who was gazing interestedly through the little window of their compartment, gave a cry of surprise. “Things have certainly been happening here since we last saw this place,” he said. “Look!” Stanley, too, peered through the window. A number of long, wide, wooden buildings had been erected along one side of a level field. There were also narrower and higher structures and a small cluster of tents. Men in uniform were drilling near the group of buildings; and a detachment of other soldiers was signalling with large white panels that were spread out on the ground. “Ted,” he said suddenly, “that aviation-field has been put there for a purpose. It may mean that the war fever has spread even to these remote countries; or it may be only the beginning of a preparedness campaign. I can’t say why, but I feel in my bones that we are going to get mixed up in whatever it is before very long.” “I hope not. We can’t afford to let anything sidetrack us from getting that gold. If we keep putting it off something may happen to prevent our getting it altogether.” “But that is just what I am thinking,” Stanley protested. “Everything we do must be a step toward the big goal.” “I don’t see the connection.” “Well, then, let me tell you. It takes many days of walking over the most difficult trail to reach the underground river. And heaven only knows how hard it will be to carry the gold back up the mountainside. Now, in an airplane the distance cannot be very great, and instead of work it would be fun. Now do you see what I mean?” “Stanley!” Ted’s face beamed. “Do you think we could arrange it?”