Fortunately Jessup's directions had been explicit, and toward noon Buck found the spring at the bottom of a small canyon and proceeded to unpack and settle down. Bud himself had discovered the place by accident, and as far as Stratton could judge it was not a likely spot to be visited either by the Shoe-Bar hands or their Mexican confederates. A wide, overhanging ledge provided shelter for himself, and there was plenty of forage in sight for the two horses. Taken all in all, it was as snug a retreat as any one could wish, and Buck congratulated himself on having such safe and secluded headquarters from which to carry on his investigations. These first took him southward, and for five days he rode through the hills, traversing gullies and canyons, and spying out the whole country generally, in a systematic effort to find the route taken by the rustlers in driving off their booty. Once he found the spot where they had taken to the hills, the rest was comparatively simple. There were a number of signs to guide him, including the bodies of two animals bearing the familiar brand, and he succeeded in tracing the thieves to a point on the edge of a stretch of desert twenty miles or more below the Shoe-Bar land. About twelve miles beyond lay another range of hills, which would give them cover until they were within a short distance of the border. "A dozen good fellows stationed here," thought Stratton, critically surveying the gully behind him, "would catch them without any trouble. There's no other way I've seen of getting out with a bunch of cattle." Having settled this point to his satisfaction, Buck's mind veered swiftly--with an odd sense of relief that now at last he could investigate the matter seriously--to the other problem which had stirred his curiosity so long. When his attention was first attracted to the north pasture by Bud's account of Andrew Thorne's tragic death, its connection with the mystery of the ranch seemed trivial. But for some reason the thing stuck in his mind, returning again and again with a teasing persistence and gaining each time in significance. From much thinking about it, Buck could almost reconstruct the scene, with its familiar, humdrum background of bawling calves, lowing mothers, dust, hot irons, swearing, sweating men, and all the other accompaniments of the spring branding. That was the picture into which Thorne had suddenly ridden, his face stamped with an excitement in marked contrast to his usual phlegmatic calm. In his mind's eye Stratton could see him clutch Tex Lynch and draw him hastily to one side, could imagine vividly the low-voiced conversation that followed, the hurried saddling of a fresh horse, and the swift departure of the two northward--to what?