Forty Mile, so called because the river of that name enters the Yukon forty miles above the Boundary, was a considerable camp prior to the Dawson boom, but thereafter it had languished, and this winter it was all but deserted.  So, too, was Cudahy, the rival trading-post a half-mile below.  It was on the bars of this stream that the earliest pioneers had first found gold.  Here at its mouth, during the famine days before the steamboats came, they had cached their supplies; here they had brewed their hootch in the fall and held high carnival to celebrate their good luck or to drown their ill-fortune.

Rock and his companion pulled up the bank and in among the windowless cabins during the afternoon; they had halted their dogs before the Mounted Police station, only to find the building locked and cold.  The few faithful Forty-Milers who came out to exchange greetings explained that both occupants of the barracks had gone down-river to succor some sick Indians.

Rock was disgusted, but his next question elicited information that cheered him.  Yes, a pair of strangers had just passed through, one of them an active, heavy-set fellow, the other a tall, dark, sinister man with black eyes and a stormy demeanor.  They had come fast and they had tarried only long enough to feed their dogs and to make some inquiries.  Upon learning that the local police were on the main river somewhere below, they had held a consultation and then had headed up the Forty Mile.

“Up Forty Mile?” Rock cried, in surprise.  “Are you sure?”

“We seen ’em go,” his informant declared.  “That’s what made us think there was something wrong.  That’s why we been on the lookout for you.  We figgered they was on the dodge and hard pressed, but we couldn’t do nothing about it.  You see, it’s only about twenty-three miles to the Line up Forty Mile.  Down the Yukon it’s forty.  They been gone ’most two hours, now.”

“What do you want ’em for?” another bystander inquired.

“Murder,” Rock exclaimed, shortly; then he heaved his sled into motion once more, for ’Poleon had started his team and was making off through the town.  Down into the bed of the smaller stream the pursuers made their way and up this they turned.  Again they urged their dogs into a run.  It took some effort to maintain a galloping pace now, for the teams were tiring, and after some mental calculations Rock shook his head doubtfully.  Of course, his quarry was at a disadvantage, there being two men to one sled, but—­ twenty-three miles, with a two-hour start!  It was altogether too great a handicap.  The lieutenant had figured on that last forty miles, the last five or ten, in fact, but this change of direction had upset all his plans and his estimates.  Evidently the McCaskeys cared not how nor where they crossed the Line, so long as they crossed it quickly and got Canadian territory behind them.  Barring accident, therefore, which was extremely unlikely, Rock told himself regretfully