"I see a cave up there," said Donner, pointing above to ledges and boulders.

24 "It's just possible we may find something in it. You boys go on ahead. I'll come after you. I'm not in very good condition for climbing."

In a moment Joe Hardy was working his way nimbly up the gray rock wall. Frank and Chet followed close behind. Above them, the cave mouth was a black opening in the rocks.

Soon Joe reached a narrow cross ledge about a third of the way up. As he pulled himself onto it, however, he was suddenly staggered by a stone that crashed into his forehead.

70 "Look out! Above you!" Donner shouted.

Other stones came bouncing down at the climbing boys, narrowly missing them.

Looking up, they saw a tall, lean figure at the top of the hollow. He kept hurling the dangerous missiles.

"It's Simon!" cried Donner. "Watch out!"

The mute boy waved his arms threateningly.

"He's trying to stop us from coming up," Joe said grimly. "Well, he's not going to succeed!"

Though his head was bleeding, the plucky boy crawled upward again after Frank, who was now in the lead. Chet was climbing at a slower pace behind them.

Seeing the trio advance, the strange boy redoubled his barrage.

One stone bruised Frank's forearm. Another skipped off his back. Dodging, the determined boy crawled steadily upward. He reached the ledge at the mouth of the cave, then he turned, and with a skillful pull and twist, hauled his brother up beside him.

Abruptly the stoning ceased. Frank and Joe turned to face the cave itself. The next instant they froze in their tracks. Barely three feet from their faces a deadly timber rattler was coiling to strike!

At that moment two more of the venomous snakes slithered out of the cave itself!

CHAPTER IX.

Setting a Trap there was no escape for the Hardys-the ledge was too narrow. They were trapped by the deadly reptiles. The steep drop below the cave cut off all chance of rapid descent. While the two rattlers slithered toward their exposed ankles, Frank and Joe raised their arms in an attempt to ward off the strike of the reptile coiled just above them.

Crack! The shot of a pistol was followed in a split second by the unmistakable smack of a bullet hitting home. The snake's long body exploded straight upward, writhing, and then fell with a thud at the Hardys' feet. Startled, the two other rattlers retreated into the cave.

"Off the ledge, quick!" cried Frank.

Scrambling backward, both boys hung for an instant by their finger tips from the ledge. In another moment they were grasped firmly by Chet Morton and Walter Donner, who had climbed up the steep rock face. Donner held in one hand the smoking, long-barreled pistol which had ended the life of the deadly snake.

When the four climbers were back on the ground, Sheriff Ecker wiped his brow in relief. "A close call," he declared, still shaken. "Wasn't a thing we could do!"

"Lucky for us you decided to come up, Mr. Donner," Joe addressed the tall man gratefully. "And even luckier you can shoot so well."

"We're certainly thankful you were near enough to shoot," Frank added. "Your bullet must have caught that rattler right in the head!"

Walter Donner's face, usually so good-natured, had become serious, and even stern.

"I'm glad I happened to be here," he answered. "I hate to think of what would have happened otherwise. Suppose you boys had gone rushing up to that cave, without looking where you were going, and I wasn't around? It would have been 25 a terrible tragedy!"

Putting one arm around Chet's shoulders, and another around Joe, Donner continued, "If you ever listened to anything, listen to me now. You can't be too careful in the woods! You never know where danger is going to come fromsometimes under your feet, sometimes over your heads. Snakes like to sun themselves on dry, rocky ledges. Don't climb around carelessly. Once 73 you are in the wilderness, remember-caution, boys, always caution."

"Mr. Donner," one of the deputies said emphatically, "I've got two boys at home, and I couldn't have said it better to 'em than you just did."

"Yep," another agreed. "The woods is no place for kid stuff. You've got to be on the lookout."

"It's true," Sheriff Ecker put in. "Most people who get in trouble in the woods just don't know any better. They can't tell directions, they're not careful where they step, they forget to bring matches, and so on. Always somebody coming up from town and getting lost in these mountains."

"Well"-Donner's voice became jovial again -"I'm sure these lads are going to be real careful after what happened today." He turned to the Hardys. "Maybe you'd better stay out of Black Hollow entirely. It's a dangerous place, especially with that Simon throwing rocks at people. Besides, it seems certain your friend isn't here."

Thwarted and disappointed at finding no trace of the missing captain, Frank, Joe, and Chet thanked the search party and returned to their cabin. Frank washed and dressed the stone cut on his brother's head.

"How's it feel?" he asked.

"Terrible-I have a corker of a headache."

While Joe lay down to rest, Frank again studied 74 the calendar notations made by the captain. Chet Morton busied himself getting supper. When it was ready, the stout boy called out cheerily: "Soup's on. Come and get it!"

Although Chet had outdone himself to produce a meal of steak, fried potatoes, and hot vegetables, the brothers hardly seemed to notice the food. They ate in thoughtful silence. Chet watched his two friends uneasily.

"Still feeling blue about it?" he asked at last.

"About what, Chet?"

"About that lecture Donner gave us. He sure made it sound as if we're babes in the woods. Boy, did that get me mad for a minute there! Why, the three of us have been camping for years. I felt like telling him a thing or two!"

"So did I, Chet," Joe admitted ruefully. "But I couldn't, because he'd just saved our lives. It really looked as if we were babes in the woods."

"Let's be fair, fellows," Frank put in. "It's true we're not tenderfeet, but what happened was our own fault. We should have thought of the possibility of snakes. I know they're apt to be in rocks as well as Donner does. ..."

A new idea suddenly crossed Frank's mind. ". . . as well as Donner does," he repeated thoughtfully. "If he knows it, why didn't he warn us before we went up? Besides, he knows more than that. He knows every rock and tree in Black Hollow, as Sheriff Ecker told us. We trusted 75 Dormer's knowledge of the hollow-that's why we weren't careful. But who sent us up to that cave? Donner!"

"That's right!" Joe chimed in excitedly. "And remember, he invited us to give up the search, and stay out of the hollow. There's something fishy about that man and his house. I know I heard a door open in the back. But there wasn't any sign of one in the kitchen."

"What I can't figure out," Frank went on, "is why Donner would send us up to a den of rattlers and then save our lives. Because the only reason he climbed up along with us was to get within pistol range of the snakes. The sheriff and his men couldn't shoot-we were in their line of fire."

"There's your answer," Joe declared forcefully. "I believe it was Donner's 26 idea to establish us as woefully inexperienced in front of witnesses. Suppose some 'accident' does happen to us down there. The sheriff won't be suspicious, because he thinks we don't know how to take care of ourselves!"

"You mean Donner may be planning to kill us and make it look like an accident?" Chet asked.

"Who knows?" Frank nodded seriously. "Another thing-the rock throwing by Simon, the mute. Is he in league with Donner? Or was he perhaps throwing stones at us because we were with Donner?"

76 Joe frowned. "It's a puzzler, all right, including Donner's resemblance to Colonel Thunder."

"Hey-I nearly forgot!" Frank reached into his pocket and placed a shiny metal disk on the table.

"What's this?" asked Chet, picking it up. "Oh, a dog tag. What's it say?

Skippy! That's Bobby Thompson's little dog! Where'd you find this?"

"In the gra.s.s near Donner's front door."

"You think Donner's been stealing dogs?" Joe queried. "Is he mixed up in some kind of animal racket? He said himself there was an illegal market for dogs."

Perplexed, Frank shook his head. "You have me there. If he steals them, I can't figure out what he does with them. There weren't any around his house."

"That's true," Chet agreed. "I took another look in the sheep pen. Nothing in it but sheep. Could be that Skippy just wandered off from the Thompsons' and lost his tag down by Donner's."

At that moment the boys' own puppy could be heard noisily lapping up warm milk from a pan that Chet had put down for him.

"We can't let anything happen to Mystery I" Chet finished anxiously.

Hearing his name, the beagle romped happily over to Chefs chair. "Yes, Mystery," the chunky boy crooned, while the dog's tail thumped the floor, "we won't let anything happen to you!"

77 "All the same, I think tonight is the time to set our trap for the dog thief,"

Frank declared.

"Right," Joe agreed promptly. "Mystery, old pup, you're going to be the bait."

"Now wait a minute, fellows," diet protested. "I won't agree to this unless I'm sure we can safeguard Mystery!"

"I think we can," said Frank. "We'll just tie him on the porch after dark.

Chet and Joe-you watch from right inside the door at all times. I'll hide at the side of the house. That way, we ought to catch any dognaper that comes around!"

Accordingly, about ten o'clock, the gasoline lanterns were turned out, and the little cabin was in solid darkness. Heavy clouds, promising a storm later on, had begun rolling across the sky. The air was dense and still.

Chet and Joe opened the cabin door quietly, and led Mystery outside. After securing the dog's rope to the railing, the two withdrew to stand guard. From within they could scarcely make out the dog in the total darkness.

Soon afterward Frank, wearing dark clothes, slipped out the back door and stationed himself between Captain Maguire's old car and the side of the cabin, a few steps from the porch.

The youth sat down and waited, listening intently. Gradually his eyes became accustomed to the night. Even so, he realized that a person advancing across the clearing against the back78 ground of thick trees would be nearly impossible to see.

The night air seemed to grow heavier and warmer. Flickers of lightning began to play about the horizon. The thunder became louder. Suddenly a streak of lightning lit up the clearing for a bare instant, then blackness closed down again. A tremendous thunderclap followed instantly. Frank checked his watch.

It was nearly midnight.

Another flash came, accompanied by a long roll of thunder. On the porch the 27 beagle whined.

"Storm's almost on top of us," Frank noted.

Almost immediately came another white blaze of lightning, and a fearful crash of thunder. The first heavy drops of rain pelted down. Mystery's whines suddenly changed to frantic, high-pitched barking.

Distracted for a moment by the storm's arrival, Frank hesitated an instant, then sprang forward. At that same moment Joe and Chet burst out the front door.

Mystery was gone!

The dog's yelping could be heard, but the sound grew fainter. A sheet of lightning made the clearing and woods even brighter than day. Frank, Joe, and Chet caught sight of a figure fleeing swiftly down the path into the hollow.

"After him!" Joe shouted.

Armed with flashlights, the three boys raced in pursuit.

CHAPTER X.

Sketch of a Thief sprinting across the clearing, Frank, Joe, and Chet entered the dark woods on a run. They were forced to slow up at once, however, in order to pick out the path with their flashlights.

Ahead of them, the dog thief pounded forward in the darkness, apparently certain of his way even without a light. Mystery's whimpers came back to the boys, then were drowned in a rumble of thunder. Raindrops could be heard pattering on the tree leaves overhead. In the momentary glare of lightning flashes, the three boys could see a figure ahead running swiftly downward toward the floor of the hollow.

Suddenly, from the blackness, came a human cry, followed by the clatter of something or somebody falling among the rocks, then a heavy crashing in the underbrush. All the while Mystery barked frantically.

Recklessly the pursuers dashed to the bottom of the path. Someone was groaning in pain in the dense underbrush to their right. The sound of running footsteps continued.

"Joe! Chet!" Frank commanded breathlessly. "Find out what's going on in the brush. I'll keep after the thief!"

"Roger!" snapped Joe.

With flashlight beams darting here and there, Joe and Chet moved forward through the dense growth. The crashing of bushes told them their quarry was moving, too. But no more groans reached their ears. Soon they could hear nothing but the sound of the rain falling heavily on the leaves, and the claps of thunder.

"No use. We've lost him," Joe decided quickly. "Back to the path, Chet."

In the meantime, Frank had been able to increase his speed on the level valley floor. Hoping to catch the fleeing figure off guard, the youth no longer used his flashlight, but relied instead on the lightning's vivid glare.

Suddenly, as the woods was illuminated by an especially dazzling flash, Frank recognized the tall, thin figure running just thirty yards ahead with a wriggling object under one arm. "Simon!" Frank called out. "Wait!"

But the strange boy wheeled and made a dash for the rocky side of the hollow.

Limping slightly as though hurt, but still with 81 amazing agility, Simon clambered swiftly upward over the rocks. Frank had almost closed the gap between them in a final spring. Bounding upward himself, he made a lunge and grasped the fleeing boy's ankle firmly with one hand.

Mystery, barking fiercely, was thrown clear. Simon, who had been dragged backward, suddenly recovered and threw himself upon Frank.

By now the storm was at its height. The rain fell in sheets. Flickers of lightning illuminated the fierce struggle between the two boys.

Keeping a cool head, Frank tried to subdue the boy by means of a wrestling hold. But Simon's wet clothing and his unexpected, immense strength enabled 28 him to wrench free, throwing Frank to the ground. Quickly Simon grabbed a heavy rock and poised it above Frank's head.

"Drop it!" came a sudden shout from below.