As Alec could not think of staying back when the rest were bent on learning the secret of all that terrible clamor of human voices raised in angry shouts and whoops, he took his place alongside Hugh, and they all started forth.

“One thing sure, to begin with,” remarked Hugh, after they had left the camp behind them, “we’re a unit in saying that racket came from where we happen to know the old castle lies.”

“Oh! that’s an easy nut to crack!” declared Monkey Stallings.  “The sounds came right down the wind, and any one can see it’s blowing softly straight from the haunted mansion.”

“We might guess that the ghosts were having a hop all by themselves,” ventured Billy, “only you know they say spirits never show themselves in the daytime.  Anyway, those whoops were more like wild Injuns on the warpath than just spooks.”

“Well, as we don’t happen to have any Indians left in this region nowadays,” added Hugh, drily, “we can put that explanation down as impossible.  But we’ll know more about it before three minutes more have passed, because, unless I miss my guess, we can glimpse the castle when we strike that rock yonder.  I remember taking a look back as we came along, so as to impress distances and direction on my mind, and could see the whole structure looming up.”

“Whee! listen again, will you?” exclaimed Billy, aghast.

The strange noise had again broken out.  They could hear many husky voices shouting in unison, and, besides, there were other odd sounds such as might be made by a small army of desperate assailants beating wildly against that stout door of the lonely castle.

No wonder the five boys stared at one another, with vacant looks on their several faces.  It would have puzzled smarter people than they pretended to be to analyze such a remarkable jumble of noises as their ears now caught.

Hugh would not let them stop for a second.  Indeed, if anything, he hurried them along faster than ever, as though fully determined to have the mystery cleared up without further loss of time.  If Billy’s footsteps were inclined to make him linger behind his mates he bestirred himself to assume a faster gait, for at such a critical moment the fat scout did not wish to find himself left in the lurch.

The horrid din continued as they hurried forward.  If anything it grew more and more maddening, causing the boys to shiver with mingled impatience and alarm.

Now they were close on the rock mentioned by Hugh.  In another ten seconds they would be able to at least see the walls of the grim castle in the near distance.  Billy wondered whether, after all, they might not discover that there was not the slightest sign of a living human being in sight.  He was rapidly coming to believe there might be something ghostly about these sounds.  Billy was just then in a fit condition to believe anything, no matter how absurd, for his poor heart was fluttering in his manly bosom just as you have doubtless felt the tiny organ of a bird throb when you held the frightened thing in your hand.