A vigorous blaze having been started, Mul-tal-la took the lead as before. It was understood that he was to hold his place considerably farther in advance than usual. Upon the first sign of their enemies he would warn them by signal, when they could conceal themselves, if possible, until the hostiles passed down the trail to the supposed camp. If this could be accomplished, the danger would be past and the problem solved. Everything depended upon the skill of the Blackfoot. Night had begun closing in when the start was made in the order named, excepting that Mul-tal-la, as has been stated, led by a longer interval, and Victor Shelton was at the extreme rear. The guide was invisible to the boys most of the time. The trail steadily ascended, and for an hour or more was easy traveling. It wound to the right or left, passing into deep hollows, climbing steep ridges, circling obstructions in the form of massive piles of rocks, but without interposing any difficult places where it was necessary to halt or grope one’s way. The little company had penetrated more than a mile in this manner without hearing or seeing anything to cause alarm. Mul-tal-la was beyond sight, but the boys, George leading, were silent, listening and peering into the gloom, which, as yet, was unlighted by the moon. That would not rise for some time to come. Suddenly a soft tremulous whistle came from the front. This was the signal agreed upon, and the brothers instantly halted. Zigzag was so well trained that he did the same. It had been deemed best to place him between Jack and Prince, so as to hem him in, as may be said. Fortunately the check came at a favorable point. The rocks and undergrowth on the right offered a good place for hiding, and George Shelton, slipping from his saddle, grasped the bridle rein of his horse and forced him to one side. The animal stumbled, but a few steps took him far enough. Leaving him, George dashed back to Zigzag, and with harder work almost dragged him after Jack. Victor was on the ground almost as soon as his brother, so that the boys and three horses were speedily bunched together, beyond sight of anyone passing over the trail unless his attention was drawn to them. Quick as they had been the precaution was not a minute too soon. Mul-tal-la must have failed to discover his peril until it was almost upon him. The first warning was a singular one. A sneeze sounded, followed by a guttural exclamation, and the next moment the crouching lads saw the dim outlines of a warrior striding stealthily over the pass to the eastward. He was moving slowly, with head thrust forward, and carried a long bow in his hand. Before he passed out of sight a second loomed to view, then a third, a fourth and a fifth—all gliding like so many phantoms of the night, and doubtless making for the supposed camp of the travelers a mile or more away.