Indians often select the hour just before dawn to strike their enemies, because at that time man usually sleeps more deeply. But to make a forced march and lay an ambuscade in the middle of the night--well, this proved Oak Heart’s mastery of his tribe. Buffalo Bill suspected that the herd of deer had been frightened by something more than a single redskin--or a small scouting-party of them. He knew Oak Heart’s abilities and respected them. Rash as the scout might be at times, he never took foolish chances. To lead the rescue-party into the head of the cañon might bring it to complete ruin. “Judd! you take the west side of that gorge, and I’ll go east,” he commanded his brother scout. “How’ll I communicate? Signal?” “No! If there are many of the reds they have already frightened away most of the small animals that we might imitate, and to give a bird-call would utterly ruin us. No bird will be waking up at this time o’ night--ugh!” “Well, what then?” demanded the other. “Never mind what you find, keep still. Meet me here--in twenty minutes if possible; not later than half an hour from now, at most.” “Half an hour?” “Yep. And remember, a confounded lot can happen in half an hour,” added Cody, with a chuckle. CHAPTER XI. A BUSY HALF-HOUR. Buffalo Bill had spoken a truer word than he thought. A great deal may happen in thirty minutes, and the Border King, as he separated from his brother scout, was unconsciously approaching a series of startling and perilous happenings. The moment the darkness had wiped Judd out of sight the wary scout turned eastward from the trail. The brush was thick and hung heavy with the dew of the mountains--and that might as well be rain. Every twig he touched communicated to its parent branch a shiver that showered him like a patent bath. He kept the lock of his magazine rifle under his armpit, pulled down the brim of his sombrero to shield his face, and walked swiftly on for some few yards. Yet he made wonderfully little noise. Having begun to climb rising ground, he here bore off toward the gorge, or cañon. If Oak Heart had laid an ambush there, the reds would be hiding in the brush, behind logs, and sheltered by boulders, all along the sidehills for some hundreds of yards. Buffalo Bill proposed to make a wide enough détour to get well behind the ambushed foe. By chance, however, he came suddenly upon a slope of gravel and sand, and stepped upon it before he realized the shifting nature of the soil. A stream of small pebbles began rattling down the hill! Instantly Buffalo Bill learned that his suspicions had been well founded. The Indians were there. He heard a startled grunt below him. Then in Sioux a voice asked a brief question. “Bear?” returned a second Indian.