He had gone only a few feet, however, while the boys were debating as to what was the best course for them to pursue, when he again stopped, and they could just make out that he was bending over another still shadow on the ground. It was becoming ghastly. Was he in reality a spy? Or was he, after all, one of those most despicable of all human beings, a ghoul, prowling about in the night, robbing the helpless, plundering the dead? There was but one way to find out; there was but one course open to them. They must follow out Tom’s plan, without further delay, and if possible come upon the man before he scented danger or knew of their presence, capturing him in the very act of his search. A hasty council was held. They could go back and get assistance from some of the Engineers, but this possibility held no weight with them. They would trap and take the man themselves. And with this decided upon, it then was agreed that Tom should circle forward on the right of the stranger, while George Harper carried out a like flanking movement on the left, leaving Ollie to creep almost directly forward after he had given them sufficient time to begin closing in. All three were to arrive as a human net about the man as nearly as possible at the same time. As Tom and Harper crept away and out of sight, Ollie remained standing where they had left him, his gaze glued to one spot, never for an instant taking his eyes from the swiftly-working man of mystery, except in those rare snatches when, to retain a clear vision, he had to look away and blink several times in quick succession when he found the constant stare dimming his sight and blurring his perspective. Scarcely time enough had elapsed, however, for Tom and George to get well under way on their perilous mission, when the stranger turned suddenly from his work, gazed long and steadily in the direction from which Ollie knew Tom Walton would be approaching, his whole attention concentrated upon something out there which Ollie could not see. Instinctively Ollie raised his revolver, training it upon him, ready to fire at the first indication that Tom himself was in danger of being shot or ambushed. But if the man was armed, he evidently had no taste for thus attracting general attention to himself, except in the direst emergency. From his actions it seemed equally certain that he either had seen or heard Tom approaching, or by that sixth sense of intuition, sensed his danger without knowing exactly what it was or where it lay. Even as Ollie stood there, silently alert, covering the fellow with his gun, the latter dropped suddenly flat upon the ground and like a writhing serpent began to glide quickly forward and into the gloom ahead. As he did so his form was no longer shadowed against the sky line—in fact could be discerned only occasionally and with difficulty as he sped along with almost incredible agility.