The young man bent his head in the attitude of listening when he removed the horn from his lips, and faintly to his ears came the sound resembling the far-off echo of his own horn. A smile passed over his face. “Ah! they have heard it, and have replied. Now my good Dart”--patting his pony’s neck--“we have a hard ride before us--ah, there they go!” He raised his head as he spoke, and from behind the crest of a hill nearly a mile away, he saw a dozen or more mounted Sioux Indians emerge, riding at a wild, reckless speed down toward Clontarf’s Post. They were hideous with war-paint, and decked and plumed in all the paraphernalia of savage warfare. It was plain to be seen that their mission was one of death and destruction. And it was still plainer that they had marked Clontarf’s Post as their point of beginning. Evidently they had seen the men leaving the post, and had determined to take advantage of their absence and destroy their stronghold and slay their women and children. Rollo, the ranger, put spur and dashed away, keeping to the right of the Indians and watching them all the while with a curious expression upon his face. By a circuitous route he reached the river about a mile above the post. The banks of the stream were low and unobstructed, and scarcely checking his speed, the ranger spurred his foam-flecked animal into the river and swam it across to the opposite side, and then dashed away in the deep shadows of the great, green woods. CHAPTER II. THE “HALTER” OF JUSTICE. Clontarf’s Post had first been settled by Lionel Clontarf, a gentleman of Irish descent. It was among the first settlements of the then territory of Iowa, and, although in the midst of privations, and harassed by the red man, it grew and prospered as but few under similar circumstances would have done. Family after family, with brave hearts and willing hands, were added to the settlement, until it numbered some fifty souls. Stock-raising and agriculture were the chief objects of the settlers, though in course of time a store and Indian trading-post were opened. At this point, all the surrounding settlements--which in fact were few--obtained their supplies, and many dollars’ worth of furs and peltries were brought here and exchanged by the Indians for flour, powder, and ammunition of all kinds, and such trinkets as pleased their savage fancy or wants. The settlers did all within their power to keep up a friendly intercourse between themselves and the Indians. This they would have had no trouble in doing, but for the influence of unprincipled white men, who, driven from the society of their own race, sought shelter within the red man’s lodges, or the mountain fastnesses, where they organized themselves into bands to rob and murder the unoffending settler or emigrant.