As Lennon drove his heavily packed burro over the round of the ridge above the camp spring, all the desolate Arizona waste around him was transformed by the splendour of dawn. Up out of mysterious velvety blue-black valleys loomed the massive purple-walled fortresses and cities of the mountain giants, guarded by titanic skyward towering pyramids and turrets of exquisite rose pink.

The burro was not interested in scenery or light effects. He topped the ridge and plodded slowly down the steep trail on the far side. Lennon lingered to enjoy the glorious illusion of the view.

All too soon, as the glaring sun cleared the high plateau on the eastern horizon, the ethereal colours of daybreak faded. The magic towers and pyramids lowered and shrank in bulk until they became only bald rugged peaks and buttes.

No less remorselessly the flood of hot white sunrays burned away the shadow tapestry of the valleys. In place of the cool mysterious vales there were left only scorched gulleys and dry washes sparsely set with greasewood and sagebrush and cactus.

Yet the interest in Lennon's alert gray eyes increased rather than lessened as he swung away down slope after his burro. The trail he was following was very old. Above almost every arable valley bottom the heights were crested with the stone ruins of ancient pueblos. Not improbably, Coronado or others of the early Spanish explorers had ridden this trail, west and north around the great bend, into the territory of the Moquis and Navahos.

Within the memory of settlers not yet white-haired, more than one war-party of renegade Apaches had sneaked along the ancient way in search of victims. Every few yards of the bad lands offered perfect lurking places for liers-in-wait along the trail.

Lennon glanced at the butt of his rifle in its sheath on the burro's pack. He recalled the tales of the old prospector whose copper mine he was seeking to rediscover. But his glance was only momentary. He knew that twenty-seven years had passed since the last murderous Indian outbreak in this land of desolation.

In those days a lone prospector would never have thought of tramping this trail without his rifle ready in hand, and the hammer at half cock. Lennon began to whistle a dance tune as he sauntered unconcernedly at the heels of his slow-moving burro up a rise and along a badly broken rocky slope.

They came down into a sandy wash that curved out of the mass of jagged ridges on the north. When midway across the bottom of the arroyo Lennon heard a sharp ping close above his ear—his sombrero whirled from his head. Before the hat struck the sand the rocky sides of the wash reverberated with the report of a rifle shot.

Lennon had never before been under fire, yet his reaction to the shot was almost instantaneous. One jump brought him alongside the burro. He crouched below the level of the pack and clutched the butt of his sheathed rifle. Again the gulley walls reverberated. The burro dropped dead, with a bullet through his head.

As the beast fell, Lennon hit the sand almost at the same moment, his rifle gripped in his right hand. Flattened out behind the inert body of the burro, he peered around the end of the pack. A bullet thwacked in the sand close at his right. He thought he could see a haze of semi-smokeless powder vapour above a jagged crag up-slope where the wash twisted in a sharp bend. He fired four shots in quick succession at promising notches in the crag.

Immediately after his fourth shot an arm and rifle were thrust up above the rock in a convulsive gesture, then suddenly disappeared. No more bullets came pinging down the arroyo.

Lennon gathered himself together and bounded on across the bottom of the wash to where the trail ran up a small side gully. From the gully he started to creep with cautious slowness up the left bank of the arroyo, under cover of the rocks and jutting points.

Now crawling, now springing from rock to rock, he worked his way half up to the crag, yet failed to catch a single glimpse of the lier-in-wait or to draw another shot. His conviction that he had killed the lurker became so firm that he stood erect to cover the remaining distance at a rush.

From down across the arroyo came a sharp clatter of hoofs. He whirled, with his rifle at his shoulder. Over the barrel he saw a scraggy pony loping down into the wash along the trail of the burro. The pony's rider was armed with a rifle. Lennon took quick aim—only to drop the muzzle of his weapon. The rider had flung up a gauntleted hand, palm outward. A musical feminine hail rang aslant the arroyo:

"Wa-hoo! Friend! Don't shoot!"

Lennon had already perceived that the rider was a woman. He jumped clear of the bank and sprinted down the rocky, sandy bed of the wash.

"Get off!" he shouted. "Hide behind your horse—quick! Danger."

The rider brought her pony to an abrupt halt below the dead burro and dropped out of her saddle on the far side. Only her old cowboy sombrero, the bottom of her khaki divided-skirt and her high laced boots were visible to Lennon.

With a startled snort, the ewe-necked pony plunged and backed around, clear of his motionless mistress. Lennon's first glance showed him that she was young and more than pretty. He was already leaping over the dead burro and brought up close before the girl to shield her with his body.

"Down!" he cried. "Down, before he fires!"

The dark eyes of the girl met his anxious look with a cool, level gaze. Her cheeks were ruddy with rich colour under their deep coat of tan. The corners of her rather large, but shapely mouth quirked in an amused half smile.

"Don't tell me you're not a tenderfoot," she rallied, in a softly vibrant, contralto voice. "I heard shots, so came a-running. Your attacker must have vamosed, else you'd have collected lead on the jump."

"That's so," agreed Lennon. "Only I really think I nailed the beggar. Yet you must take no chances. Get under cover while I make sure."

"You've already done that—standing here ten seconds without drawing a shot. When a mountain lion misses his game first crack, he sometimes is so shamed he clears out. Same way with a broncho Apache."

"Apache? But I thought all Indians were now on reservations."

The girl dropped the reins of her skittish, snorting pony and picked up Lennon's new sombrero. Through the middle of the high peak was a neatly drilled bullet hole.

"Poor shot—for an Apache," she said. "Good, though, for ventilation."

The dry humour of this brought a twinkle into the Easterner's gray eyes. He took the hat from her outstretched gloved hand, but paused with it half raised to his close-cropped head.

"If you'll permit me ... my name is Lennon—Jack Lennon—mining engineer."

"Engineer is all right, but can you shoot?" queried the girl.

"I have had pretty good luck with running deer. This is my first man."

"All right, Mr. Lennon. I'm going up to look for signs. Come along if you want to."

"No, you must stay here. I insist——"

But the girl was already swinging away up the bed of the arroyo, her spurs jingling on the stones. Lennon started to block the way but changed his mind when he perceived her amused smile. Instead of trying to stop her, he attempted to take the lead. The girl quickened her pace.

He had lowered more than one record in his college track meets; but the girl was accustomed to rough ground, and he was not. She was still side by side with him when he dashed up around the bend in the arroyo.

Both held their rifles ready to fire as they rushed the rear ledges of the jagged crag. From the upper side the slopes around were all open to view. Lennon came to a panting halt and stared about in frank surprise. He had fully expected to see the limp form of a dead Apache lying on the rocks.

The girl sprang past him into a niche of the crag and bent to pick up a cartridge shell.

"A thirty-two," she said. "Same calibre as my rifle.... And look at this track—Apache-made moccasin. Easy to tell the print from that of a Pima or Moqui."

To Lennon the track was only a small narrow blur.

"I was right," added the girl. "No trace of blood. You scored a clean miss and the bird has flown. All safe around here now, but may be dangerous on the trail ahead. Happens I know that a bunch of bronchos are loose over this way. They're looking for trouble."

"Bronchos? You mean wild horses—mustangs?"

"No—Apaches. Renegades are called bronchos. What do you figure on doing now, with your burro dead? Out prospecting, I noticed by your outfit. What were you heading up this way for, anyhow? The agents don't want prospectors on the Moqui or Navaho reservations."

"But I didn't intend to cross the boundary," explained Lennon. "About seventy miles on around this trail bend, I was to strike in eastward to a three-towered mountain. Old friend of mine discovered a big copper vein there in the early 'Nineties. A party of Indians ran him out of the country and so maimed him that he never could return."

"Why, that must be Cripple Sim and his——" The girl checked herself and tightened her lips. "Well, what you going to do about it? Hike back to the railroad?"

"Certainly—to get another burro. We might return together for mutual protection, unless you'd rather trust to your pony's heels."

The girl looked him up and down with sharp appraisal.

There was no hint of timidity in his smile.

"Don't figure there's any joke about a bunch of bronchos," she said. "They like to kill just for pure devilment, and when they can make it without risk, their choice of game is a white man."

"Or woman," put in Lennon, no longer smiling.

"Choicer still. But a man will do. How about that hole in your hat? Hadn't you better catch the first train East, and keep going?"

Lennon flushed, rallied himself, and smiled.

"I didn't come to Arizona for my health. I might say it was on business, but I've no objection to a bit of sport on the side."

The dark eyes of the girl flashed with a look of almost fierce intensity.

"I'll call your bluff," she challenged. "We'll see if you're four-flushing. Dead Hole—Dad's ranch—is only a few miles southeast of Triple Butte, the mountain you're headed for. I know the short cut across the Basin. Want to come along?"

"The Indians," protested Lennon. "No, do not misunderstand me, please. It is all right for a man to take chances. But a girl like you——"

"Like me? Well, the kind of girl I am is this—I'm going home. I've no mind to back up. Good-bye, Mr. Jack Lennon."

He was beside her again before she had reached the bed of the arroyo.

"I have a compass," he said. "Perhaps I'll get to your ranch even if your pony outruns me. Only trouble, I can't lug both tools and food."

The girl stopped short to draw off her glove and offer him her strong white hand.

"I'm Carmena Farley. I don't like rattlers, coyotes, or quitters."

"I may prove to be a quitter, Miss Farley, but I'd like at least to be entered for the game."

The dark-eyed daughter of Arizona looked at him searchingly.

"You will be risking the highest of all stakes—your life," she warned.

Lennon smiled. "Oh, no; not the highest. There are other things more precious."

"Maybe," she assented. "But not everybody would agree with you."