sergeant mahon was not happy in his new work. after a police experience that knew only the ranching district he found the new conditions, the new crimes and criminals, irritating and a little bewildering. none of the trailing he loved, of horse and steer; no ranchers and cowboys and rustling gunmen any longer filled the horizon of his friendships and duties. he began to fear that a few months of it would wipe from his mind all he had ever learned. even his horse was of little use, for the only path to ride, the three miles to the trestle, was quite as easy by foot or ballast train.

the limitations of his official horizon were stifling, a mere mile or two in radius. and within that circle were only a handful he could call friends, and a camp of bohunks. he hated the shadows of the forest, where life was scarcer than in the hills, where even keen wits were wasted.

here the guns of his former enemies were supplanted by knives and knuckle-dusters and clubs; and the men who wielded them were cowardly, slinking foreigners whose very appearance was repugnant. sneaky, underground, despicable crime it was, running the gamut from petty annoyance to senseless murder. none of the open-handed, bold and reasoned intelligence of the prairie criminal. it revolted him. senseless, insensate, formless, erratic, it only disgusted him with its sheer and unprofitable lawlessness. on the prairie crime meant double duty for him--to discover, then to catch the criminal; here there was no escape--once the criminal was discovered.

this offscouring of europe was little more individual to him than a chinaman; mahon was doubtful that he could pick out a second time more than a few of the bohunks. with faces dull and brainless, voices drab and lifeless, they merged into a mass of slime.

for the first time since he had donned the uniform mahon began to question his capacity for it. knowing the history of the wide effort demanded of the mounted police, he began to wonder if he could throw himself into it with credit to the force.

the only attractive feature of his new life was the friendship of the bluff, cantankerous, but kind-hearted contractor, his sunny daughter, the manly foreman, and the talkative murphy. of tressa he had so many glowing things to write in his letters to his wife that helen threatened to rush north in self-defence. thereupon he crammed one letter from start to finish with tressa torrance's praises, and defied helen to fulfil her threat.

in the course of his work the solitary part that intrigued him was the mystery of the indian. he felt that there was more there than he knew of; he had more than a suspicion that torrance was concealing from him essential facts. but there seemed no call for official action. thus far the indian was friendly; it was his nature to be silent and mysterious.

failing use for his horse, mahon spent much time in the forest. and after a time, the very shadows, and the secrecy breathed by the trees seemed to hint at revelations just round the corner. down in the camp half a thousand bohunks, with brutal murder in their hearts, would, under police eye, climb to their bunks as innocent in appearance as kittens. there in the woods, freed from observation, the bohunk was more apt to discard his mask of stupidity. somewhere there his plans were laid, orders given and received.

what the sergeant picked up little by little in the woods, small as it was and unsatisfying to his youthful impatience, sufficed to sustain his hopes. the constant meeting after work-hours with slinking bohunks who always avoided him, convinced him that something within the law was afoot, and repeated glimpses of distant groups which dribbled away when he came within sight induced him to alter his methods. more covertly he hunted, though it tried him sorely, and snatches of conversation untangled from the froth of their utterances did much to simplify his task and give more definition to his search.

somehow his mind never quite freed itself of the haunting memory of his discoveries that early day down the slope of the river bank. though the tracks were dim, he was satisfied that horses had passed that way at no distant date. suspicious at first, doubtful as the marks advanced toward the river (largely on account of certain past memories roused by peculiarities he seemed to recognise), he had later decided that what he saw was no figment of an imagination rendered more lively by the revival of the story of blue pete. certainty was added by the suspicion that efforts had been made by a master-hand to hide the tracks.

where that led he could not even guess, though at that stage his mind kept reverting to the indian.

the mysterious arrivals and disappearances of the redskin as torrance saw them was interesting enough, but they were as nothing to mahon compared with his own failure to meet the indian face to face. that was epitomised in the incident of the voice from the darkness over the trestle the night he rushed to torrance's assistance. there was little to connect torrance's inexplicable indian friend with the indian bohunk who had dived that first day over the cliff to almost certain death, but mahon had been living among inferences and deductions and a certain question was arising in his mind. still it pointed nowhere.

constable williams had told him of isolated bands of indians who had visited the camps during the previous summer, and mahon conceived the idea that with one of these braves torrance had had dealings which placed the redskin under obligation though the contractor himself might not suspect it. an indian never forgets; that was the simplest explanation.

the secrecy of the indian's movements might be accounted for by a natural reserve, and specially by a shyness before the uniform. but where was he hiding? that he was never far away was apparent. mahon added to his other duties this new trail.

he realised the difficulty of his task after several distinct twinges of that strange sense developed in the wary at being under unseen eyes. it could not be a bohunk, for the workmen were not clever enough to trail him unseen. also it was not an inimical inspection. only the indian could trail the trailer with such unerring confidence.

it was not unnatural, therefore, that as time went on the indian assumed the proportions of a gripping mystery.

on the track of the new problem, sergeant mahon took to roaming the woods by night. his reward was unexpected and unsought--it had no connection whatever with the indian. he discovered that the bohunks were meeting in their hundreds under cover of the darkness. to satisfy himself that an outside menace was not added to the perils surrounding the trestle, mahon took to inspecting the camp from hiding whenever he came on one of these gatherings. the fact that they were composed of the ordinary bohunks of the camp, on some nights almost emptying it, relieved him.

he was turning his attention more directly to these meetings in the woods, when something happened to alter his plan.