for the fifth time sergeant mahon and helen had firmly expressed their intention of retiring; the hour, they agreed, was unseemly, when now weeks of almost unbroken association stretched ahead of them. yet for the fifth time they had failed to act on their convictions.

for one thing they were impressed with the selfishness of retiring while still constable williams sat with never a flicker of sleep in his eyes. they owed him a lot for his attentions of the past few days, and there were few opportunities of squaring the account. in the rude chair he had salved from the village wreckage the big fellow was content to sit to any hour of the night, merely smoking and listening, face beaming, pleased as a child when he found something to say. for two years he had been locked there in the wilds, with never a woman but tressa torrance to whom he could speak without a blush. and, looking into the clear eyes of mrs. mahon, he blushed a little now at memories of her predecessors in that infamous end-of-steel village--blond-haired, flashing eyed, bejewelled, strident voiced hussies who had worn out their welcome in society less base.

for the sixth time mahon consulted his watch and shook his head self-reprovingly.

"half-past eleven! dissipation. and to-morrow we must dive deeper into the records of those two speeders. i don't know that i'm quite fair, williams, but i imagine torrance hasn't been taking us completely into his confidence, though he seems thoroughly stirred over this. they have me guessing--the most unlikely things, even to some silly club wager. but there isn't a club within three hundred miles. i'm off to-morrow to mile 135. torrance says the ticker is set up there. i want to talk to saskatoon."

constable williams shrugged his shoulders. "those speeders were up to something they're not telling saskatoon or any one else that we're apt to get any information from."

"that's what i'm going to find out. they couldn't go far without being seen, and they'd have to stick to the railway. there's still a gang clearing up at mile 63, i think."

"that was where i spent the night, wasn't it?" asked his wife. "there's an engineer there with his whole family and two women besides. it's a long way to be from neighbours."

"one never speaks of neighbours out here, mrs. mahon," smiled constable williams. "it makes one homesick. it's so long since we had neighbours that we've gone a bit rusty on the amenities of society. there's so little we can do for the first woman--"

"williams, you're fishing." mahon shook his head affectionately at his subordinate. "if you'd heard my wife this morning--"

"if you don't mind, dear," interrupted helen, "i prefer to give my own thanks."

"but you just said this morning you couldn't--"

"don't try, please," said williams, with a grin. he drew a sigh. "i suppose now i ought to forego a selfish pleasure and let you go to bed. if i could only look sleepy! but i feel as if bed were an interruption, a nasty, bad-dispositioned, irritating kill-joy. and you'll be heavy with the chloroform of this rare air. ah, me! just when life begins--"

"it won't go down, williams," teased mahon. "the air up here has nothing on medicine hat. not even its wildest booster would claim for the hat the poison of a manufacturing town. meteorologically it must be as far from civilisation as mile 127. the worst up here is trying to compete with the sun in the matter of sleep. in the summer one would get about three hours; in the winter there wouldn't be time to prepare meals. winter must be eerie. even now i scent it--"

he shifted suddenly in his chair. then with a dash he and williams were crowding through the open door with drawn revolvers.

through the night came the thunder of racing hoofs.

mahon knew that speed. many a time he had ridden thus, the wind whistling past his ears and the horse's mane flicking his stinging face. he knew, too, that a master-hand directed the horse he heard.

without a word the two policemen separated and dropped into the shadows on either side of the shaft of light from the doorway.

"go into the other room, helen." mahon's order was sharp and low.

on came the racing horse, the pound of its hoofs echoing through the trees like the charge of a troop, filling the vast silence with piercing fancies. echo and hoof-beats grew louder and louder; there was no other sound. at the edge of the village the horse turned from the clearing along the grade into the main street, and the echo, sharpened now by crowding walls, sent the blood tingling through the sergeant's veins.

over the pounding hoofs broke a muttering voice.

in another five seconds the horse would cross the shaft of light. mahon and williams raised their guns. the former edged out toward the narrow path. he had no thought of warning the man--he wished to see him dash into that shaft of light, that eyes might come to the aid of ears. another moment. . . .

with a slithering of hoofs the horse pulled up in mid-flight at the very edge of the beams. a voice, husky with anxiety, shouted:

"sergeant, sergeant mahon! quick! for god's sake!"

at the first sound mahon felt the blood rush to his head. his knees shook. his left hand groped to his forehead. then he wrenched himself back to his duty.

"what is it?" his voice was quiet, but he avoided the light.

slowly and soundlessly he was moving down the other edge of the light, revolver poised, eyes straining into the darkness beyond. in the dim fringe he made out the figure of a tall man leaning toward him, a pair of indian braids falling over his shoulders. mahon's eyes moved on to the horse. he started, and his teeth clicked. surely there was something familiar. . . . but his brain was tumbling madly--he would not trust it.

the indian, blinded by the light, spoke rapidly:

"they're attackin'--right away--a hundred rifles--blow up the trestle--kill the girl an' th' others!"

neither the ride nor the run was making him pant like that.

the sergeant leaped across the light and struck. with digging heels the indian swung the pinto on its hind legs, at the same time striking at the outstretched hand. but he was too late. mahon's open palm fell on whiskers' rump, and in the very midst of rearing about she leaped forward into the light.

mahon rubbed his eyes. a wild laugh came to his lips. this was no pinto. no ugly blotches there--only a dead brown. whiskers? as ridiculous as his other fancies of late. but it must be whiskers' twin sister.

the indian and his horse were gone, racing back at full speed. mahon ran to the barracks. once more he was the mounted policeman. in the doorway stood helen.

"whiskers!" she breathed in an awed voice.

"blue--"

"don't be foolish," he scoffed. "you saw the broncho. not a blotch on it. for god's sake, don't start my dreams again, helen."

williams was already cramming his bandolier with cartridges and buckling it over his shoulder. helen seized a flashlight and hurried through the back door to the stable. in thirty seconds they followed. they saw her reappear--they heard her startled call:

"gone!"

mahon stared past her into the empty stalls.