"My enlistment expires this spring," he declared. "I won't reenlist."
"Then what?" she asked, a strange limpness sounding in her voice.
"Why, then, I'll be my own man, of course."
"You won't be your own man until you've discharged your present duties," Alison said with a quick, sidewise glance.
"Of course not," he agreed. "I'll have to take you to the fort and turn you over. They're decent chaps down there. They'll make it as easy as possible for you—"
"Oh, I see," Alison interrupted. "I didn't quite understand what you meant."
"Just this," he plunged on—"I come back here as a free agent. There's a mystery in all this business that we haven't even begun to fathom. The facts as they stand make things look very black for you, but we'll get at the bottom of the affair somehow. I'll work day and night. I'll never rest until I dig out the truth. You've forced me against my reason to believe in you absolutely, and with such faith to back me, I know that I cannot fail!"
Dexter had entered the thicket beyond the treeless plateau, and was picking his way absentmindedly over the broken ground. The entrance of the cave was only a few paces distant, concealed behind a clump of bushes. As he skirted the fringe of underbrush, he discovered a trail of freshly made boot prints. The sight of the footmarks recalled him sharply to himself, and for the first time in the last half hour he thought of Devreaux. The colonel evidently was somewhere about, still waiting for his return.
Forcing his way through the screening branches, he reached the foot of the mountain slope and stood before the dark mouth of the cave. The line of footprints went inside. "Colonel Devreaux!" he called. "Oh, colonel!"
Nobody replied. But as he bent forward to look into the opening, he caught a sudden movement in the gloom, and the next instant a human figure loomed into view, and Dexter found himself staring full in the muzzle of a leveled rifle.