A valley opened below the mesa, the trail falling abruptly almost from the hoofs of the horse. Beaudry drew up and looked down. From rim to rim the meadow was perhaps half a mile across. Seen from above, the bed of it was like an emerald lake through which wound a ribbon of silver. This ribbon was Big Creek. To the right it emerged from a draw in the foothills where green reaches of forest rose tier after tier toward the purple mountains. Far up among these peaks Big Creek had its source in Lost Lake, which lay at the foot of a glacier near the top of the world. The saw-toothed range lifted its crest into a sky of violet haze. Half an hour since the sun had set in a blaze of splendor behind a crotch of the hills, but dusk had softened the vivid tints of orange and crimson and scarlet to a faint pink glow. Already the mountain silhouette had lost its sharp edge and the outlines were blurring. Soon night would sift down over the roof of the continent. The eyes of the man searched warily the valley below. They rested closely on the willows by the ford, the cottonwood grove to the left, and the big rocks beyond the creek. From its case beneath his leg he took the sawed-off shotgun loaded with buckshot. It rested on the pommel of the saddle while his long and careful scrutiny swept the panorama. The spot was an ideal one for an ambush. His unease communicated itself to the boy, who began to whimper softly. Beaudry, distressed, tried to comfort him. "Now, don't you, son--don't you. Dad ain't going to let anything hurt you-all." Presently he touched the flank of his roan with a spur and the animal began to pick its way down the steep trail among the loose rubble. Not for an instant did the rider relax his vigilance as he descended. At the ford he examined the ground carefully to make sure that nobody had crossed since the shower of the afternoon. Swinging to the saddle again, he put his horse to the water and splashed through to the opposite shore. Once more he dismounted and studied the approach to the creek. No tracks had written their story on the sand in the past few hours. Yet with every sense alert he led the way to the cottonwood grove where he intended to camp. Not till he had made a tour of the big rocks and a clump of prickly pears adjoining was his mind easy. He came back to find the boy crying. "What's the matter, big son?" he called cheerily. "Nothing a-tall to be afraid of. This nice camping-ground fits us like a coat of paint. You-all take forty winks while dad fixes up some supper." He spread his slicker and rolled his coat for a pillow, fitting it snugly to the child's head. While he lit a fire he beguiled the time with animated talk. One might have guessed that he was trying to make the little fellow forget the alarm that had been stirred in his mind. "Sing the li'l' ole hawss," commanded the boy, reducing his sobs.