Ackerman knew Humpback Butte and its surrounding valley and canyons as he knew the QE ranch, for he had spent days hunting all over that country; and he knew that the great slopes of the valley grew steadily steeper as they reached northward until they became sheer cliffs without a single way up their walls that a horse could master. A mile above Humpback Butte the walls curved inward until only a scant six hundred yards lay between them; and on the southern side of the eastern cliff, which jutted out into the valley, hidden behind an out-thrust point, was a narrow canyon leading into the valley which formed the northwestern outlet of the QE ranch. For nearly five miles north of Humpback Butte extended the valley, now a great, wide canyon; and not one of the several blind canyons in its great walls gave a way out. Anyone passing the hidden canyon would hunt in vain for an exit and have to return again. Reaching his horse, Ackerman mounted and rode north at top speed, guiding the animal over grass as he threaded his way in and out among the obstructions. Speed was the pressing need now, for if he could gain the hidden canyon before his enemy found it on his return, he had him trapped. There was an up-thrust mass of rock, covered with brush and scrub timber, which lay before the entrance of the canyon; once up on that he could command both the canyon and the valley, the greatest range not over five hundred yards. Dismounting in a thicket close to the entrance, he slipped to the canyon and looked for tracks. Finding none he clambered up on the mass of rock and searched the valley for sight of Nelson. For a quarter of a mile he could follow the winding creek and he watched for a few minutes, studying the whole width of the valley. "I've beat him; an' he ain't come back yet," he chuckled grimly. "I got five minutes to look in th' canyon an' be dead shore!" For a hundred yards the little creek flowed along the north wall of the canyon and he wasted no time on it; any man who would ride for forty miles in creeks would not forsake the water for a mere hundred yards. Running at top speed he dashed around a bend, eager for what he would find. There was a six-foot drop in the bottom of the canyon, and a small waterfall, where a rider would be forced to forsake the creek to climb the ridge. A quick glance at a wide belt of sand running out from the ledge at a place where it had crumbled into a steep slope told him that no one had passed that way, and he wheeled and ran back to gain the great pile of rock outside. "Got you!" he panted triumphantly. "Yo're a clever man, Mr. Nelson; but you can't beat a stacked deck. Here's where I pay for a certain day in Hastings!"