But the odd something which tugged at him was as persistent as the buzz in his earphones. And an idea came. If he were obeying some strange call for assistance, couldn't that in some way lead him to what he sought? The only difficulty was that he had no way of being more receptive to the impulse than he now was. He could not use it as a compass bearing.
In the end he chose the Center as his goal, reasoning that if the prisoner were to be interviewed by the leaders of the aliens, he would be taken to those rulers, they would not go to him. From a concealed place across from the open square on which the building fronted, the pilot studied it carefully. It towered several stories above the surrounding structures, to some of which it was tied by the ways above the streets. To use one of those bridges as a means of entering the headquarters would be entirely too conspicuous.
As far as the pilot was able to judge, there was only one entrance on the ground level, the wide front door with the imposing picture-covered gates. Had he had free use of the flitter he might have tried to swing down from the hovering machine after dark. But he was sure that Captain Hobart would not welcome the suggestion.
Underground? There had been those ways in that other city, a city which, though built on a much smaller scale, was not too different in general outline from this one. The idea was worth investigation.
The doorway, which had afforded him a shelter from which to spy out the land, yielded to his push, and he went through three large rooms on the ground floor, paying no attention to the strange groups of furnishings, but seeking something else, which he had luck to find in the last room, a ramp leading down.
It was in the underground that he made his first important find. They had seen ground vehicles in the city, a few still in operation, but Raf had gathered that the fuel and extra parts for the machines were now so scarce that they were only used in emergencies. Here, however, was a means of transportation quite different, a tunnel through which ran a ribbon of belt, wide enough to accommodate three or four passengers at once. It did not move, but when Raf dared to step out upon its surface, it swung under his weight. Since it ran in the general direction of the Center he decided to use it. It trembled under his tread, but he found that he could run along it making no sound.
The tunnel was not in darkness, for square plates set in the roof gave a diffused violet light. However, not too far ahead, the light was brighter, and it came from one side, not the roof. Another station on this abandoned way? The pilot approached it with caution. If his bump of direction was not altogether off, this must be either below the Center or very close to it.
The second station proved to be a junction where more than one of the elastic paths met. Though he crouched to listen for a long moment before venturing out into that open space, he could hear or see nothing which suggested that the aliens ever came down now to these levels.
They had provided an upward ramp, and Raf climbed it, only to meet his first defeat at its top. For here was no opening to admit him to the ground floor of what he hoped was the Center. Baffled by the smooth surface over which he vainly ran his hands seeking for some clue to the door, he decided that the aliens had, for some purpose of their own, walled off the lower regions. Discouraged, he returned to the junction level. But he was not content to surrender his plans so easily. Slowly he made a circuit of the platform, examining the walls and celling. He found an air shaft, a wide opening striking up into the heart of the building above.
It was covered with a grille and it was above his reach but....