It was easy, with his torch and the guiding arrows, to follow the devious, winding course of the passage. He surmised that its ascents and descents, which seemed arbitrary and unreasonable as he pursued them, were due to other entrances than the one he knew. It would be necessary, as he could understand, to have more than one means of getting in and out of such a passage. And when he found himself at last going in a straight path which sloped easily downward, he guessed that he was beyond the house, and that he had come to a part of the passage that led to the outer world.
Here there was a trace of dampness, but nothing like what might have been expected in what was really a tunnel. Fred had to admire the excellence of the construction work. The descent, as he knew from what he had seen outside, must really be very sharp. But it was managed here with turns and zigzags so that the grade was never very sharp.
Fred became suddenly conscious of a change in the air.
"I must be near the opening," he thought.
A couple of minutes proved that he was right. He now remembered that Boris had not had time to tell him how the door or gate was operated. But he decided not to go back at once, but to try to discover the secret for himself. It had occurred to him that it was more than probable that a sentry or two might be left in the house, and he had no mind to stay in the passageway, helpless and useless, if Vladimir found it impossible to let him out at once.
At the end of the passage he found a solid, seamless door. He decided at once it must work on an axis of some sort and that it must be set in motion by pressing a spring. And so, steadily and systematically, he searched the whole door, until he struck the right spot at last. As the door moved, he marked the spot with a tiny pencil mark. It swung open—and he looked into the eyes of a startled German soldier, his mouth wide open!
CHAPTER VII
A DARING RUSE