Mayhew undoubtedly had some sort of plan in mind when he beckoned the others to follow. He was an experienced scout, and knew as much about the tricky ways of the red men as any borderer of his time. It was on this account that Captain Clark had suggested that he accompany the boys on this trip, as well as to allow Mayhew a chance to repair the damage his blunder had done to their cause. Three times he abruptly changed his course. Evidently he had a reason for this, and Dick suspected that the guide must have discovered the enemy to be lying in wait for them ahead. It was thrilling, but tiresome. Roger found himself wishing heartily that something would happen to break the silence. It seemed to be oppressive, to be weighing him down as with a heavy load. Indeed, to the impulsive lad almost anything would be preferable to this terrible stillness. It was while Roger was allowing himself to give way to this feeling, and wondering whether, after all, it might not do better if they sprang to their feet and ran for it, that something did occur, and of a nature to surprise him. Crouching at the foot of a tree, and just about to slowly get to his knees in order to take an observation, Roger suddenly felt himself pulled down. Dick had seized his hunting tunic, and given it a quick, strong tug. At the same instant Roger heard an odd, whistling sound that seemed to come from a point very close to his ear; this in turn was succeeded by a little thud, such as one might make when striking his hunting knife against the bark of a tree. As the boy twisted his head around, his wondering eyes fell upon something that caused him to draw in a long quavering breath. It was the feathered shaft of a Blackfoot arrow that had its flint head buried deep in the yielding wood of the tree. In order to have reached that spot it must have passed only a few inches above Roger's body. Then the Indians _did_ know of their presence; the fact of this shaft having been sent in their direction told the story. Roger somehow found himself wondering if those stories he had heard about the Blackfoot warriors poisoning the tips of their war arrows could have any foundation in truth. It was not a pleasant thought when they found themselves at bay, surrounded by an unknown number of the savage tribesmen. But Mayhew was once more creeping on; if he did not wish to be left behind he must follow in the wake of the guide. Dick brought up the rear. It may have been accident that brought this about, and, then again, perhaps the boy had some design in taking his place at the end of the line. He knew the impulsive ways of his cousin, and that there was always a chance that Roger might get himself into trouble through lack of caution.