They rode back to the camp tents, to find Buck Tooth calmly smoking his red-stone Indian pipe, and gazing off in the darkening distance at nothing at all, as far as the boys could determine. "Anybody been around, Buck?" asked Bud. "Nope!" was the answer. "You catchum dead man?" "Not a sign, Buck! Beckon he must have dug a hole and pulled it in after him. But we've got to find out what's the matter with the pipe line. There's only a few days' supply of water in the reservoir. Rustle out some grub, and we'll ride over the mountain." "Um," grunted the Zuni, and a little later, after a hasty meal of flapjacks, bacon and coffee, the boy ranchers, with the old Zuni Indian, started on a night ride over the mountain trail, in the general direction of the pipe line, the supply of fluid for which had so mysteriously stopped. But strange events were only just beginning to happen in Flume Valley. There were others in store for the boy ranchers. CHAPTER III THE WARNING "Will it be safe to leave our camp alone, like this?" asked Nort, as he and his companions rode off, leaving behind them the white tents, gleaming in the wondrous light of a full moon. "Why not?" inquired Bud. "It won't walk away." "No, but some one might come in and take everything." "There isn't much worth taking. You brought your old stuff with you, we have our ponies, so all they could snibby would be the camp dishes, and they aren't worth the risk." "Could they drive off any of your cattle?" asked Dick. "Why don't you say _our_ cattle?" asked Bud with a smile, which was plainly to be seen in the brilliant moonlight. "You fellows are in this venture with me, you know." "We haven't yet gotten used to thinking of it that way," remarked Nort, as he rode beside Buck Tooth. The old Zuni Indian managed to keep pace beside the boys without ever urging his pony forward, a trick of riding which even Bud envied. "Well, you'd _better_ get used to it," was the laughing retort. "Your dad staked you to part of the expenses of this deal, same as mine did me, and of course you'll share in the profits--if there are any," Bud added rather dubiously. "And if we don't get that water back there won't be enough to make you need a hat to carry 'em off." "As bad as that?" inquired Nort. "Oh, I'm not saying it's bad--_yet_!" exclaimed Bud. "There may be just a stoppage in the pipe, which can easily be cleaned out. Or, it may be--something else." But what else it might be he did not say, and Nort and Dick were not sufficiently familiar with irrigation and flume lines to hazard a guess. But they knew enough about their cousin to tell that he was worried. "What do you plan to do?" asked Dick, as the four rode on, their ponies occasionally stumbling as they mounted the rocky trail that led over Snake Mountain. "Look for that man--the one you----"