The place was as silent as the grave.  Obviously no one was about here upon these nights when there was no loading and unloading going on.  In that, at least, chance had been a good friend to them.  They were going to make the most of it.  Through little runways, narrower than the main route, and so low that they had to bend their necks to get along in safety, they went, measuring and examining.  Every few yards or so they would come upon another little niche, stacked high with sacks of a similar hardness to those others back there at the beginning of their journey.  Cleek prodded one with his finger, hesitated, then slipping out a penknife, slit a fragment of the coarse sacking and inserted his thumb....

He pulled it out with a look of astonishment upon his face.

“Hello, hello!” he exclaimed.  “So that’s it, is it?  Gad!  This is the approved hiding-place!  Then those tubings—­Dollops, just a little more of this wearisome search, just a few telephone calls to be made, and I believe I shall have untied at least one part of this strange riddle.  And when that knot is unfastened, it will surely lead me to the rest....  Go on, boy.”

They went on, stepping carefully, and hesitating now and again to listen for any sound of alien footsteps.  But the place might have been the grave for any sign of human habitation that there was.  They had it to themselves that night, and made the most of it.

For some time they walked on, taking the road that most appealed to them, and in the maze must surely have retraced their own footsteps.  Of a sudden, however, they broke into a sort of rough stone passage, with concrete floor that ran on for a few yards and ended at a flight of well-made stone steps, above which was a square of polished oak, worm-eaten, heavily-carved, and surely not of this generation’s make or structure.

“Now, what the dickens...?” began Cleek, and stopped.

Dollops surveyed it with his head on one side.

“Seems ter me, sir,” he began, after a pause, “that this yere’s the genuyne article.  One of them old passages what people like King Charles and Bloody Mary an’ a few other of them celebrities you sees at Madame Tussord’s any day in the week, used to ‘ide in when things were a-gettin’ too ’ot fer ’em.  That’s what this is.”

“Your history’s a bit rocky, but your ideas are all right,” returned Cleek with a little smile, as he stood looking up at the square of black oak above them.  “I believe you’re right, Dollops.  It must have given the later arrivals a big start in that tunnelling business, or else they’ve been at it, or both.  There must be years’ work in this system of passageways.  It is marvelous.  But if it’s a genuine old secret passage, those stairs will probably lead up into a house, and—­let’s try ’em.  If the house they lead into is the one I think it is....  Well, we’ll be unravelling the rest of this riddle before the night is out!”