Frank knocked. As the man looked at them inquiringly, Frank put the question: "Pardon me, sir, but aren't you William Don-ner?"

CHAPTER XIII.

Worrisome Watching startled, the animal trainer fidgeted uneasily with the door handle.

"What gave you the idea I'm William Don-ner?" he asked.

Frank, seeing the man's embarra.s.sment, chose his words carefully.

"Well, sir, we've met a man named Walter Donner, who looks exactly like you.

When we found out that he had an identical twin brother, we put two and two together. And then, the names 'William Donner' and 'Bill Thunder' are the same-donner is the word for thunder in German."

In spite of himself, the man gave an approving smile at this last deduction.

"All right, boys," he said as he faced them once more. "I'm William Donner, and I don't sup105 106 pose it matters if anybody knows it. You see, we Donners used to be a fine, close-knit family. But when my parents died, my brother and sister and I couldn't agree on dividing the estate. So far as I know, the properties are still vacant, and the lawyers are still arguing.

"I had to make a living, so I took this job. I've always been able to train animals. I didn't want to embarra.s.s my brother and sister-they were always touchy about their social position-so I just translated the family name to Thunder."

Pausing for a moment, the tall man seemed to reflect. "So, you saw Walter! I didn't even realize he was still in this part of the country. Haven't heard from him in years. What's he doing with himself now?"

"Not much," Frank answered. "He lives in a little cabin down in Black Hollow, and raises a few sheep."

At this, the colonel raised his prominent eyebrows in disbelief. "Walter?

36 Living in that old shack? Why, that's impossible. Walter always loved luxury-couldn't do without it."

"He seems pretty comfortable, Mr. Donner," Chet put in.

"Maybe." Colonel Thunder went on. "But you don't understand what a comedown this is for my brother! I'm sorry to hear it. He's raising sheep, you say?"

"Yes," Frank answered. "In fact, we saw him Worrisome Watching 107 buying one at an auction. We thought it was you."

The colonel nodded, still reflecting on the strange news. "Funny both of us should be making a living, even a poor one, from animals," he mused. "You see, we all loved animals. Walter was different, though. He could be cruel to them, too-couldn't stand it when they disobeyed him."

"Cruel to them?" Joe Hardy picked up the words. "Would it surprise you to know, Mr. Donner, that your brother is suspected of kidnaping dogs?"

The man who called himself Colonel Thunder looked at the boys in the commanding way that seemed to be a trait of the Donner family. "Yes, it would!" he snapped, as though he himself had been insulted.

"Not only that," Frank continued with determination. "We have reason to believe that your brother is involved in the disappearance of a friend of ours, Captain Thomas Maguire."

"See here! What are you trying to pull on me?" Colonel Thunder demanded indignantly. "My twin has some strange ideas, but he wouldn't harm anybody.

What are you prying around here for, anyway? Get out! And take your ridiculous accusations with you!"

With that, he closed the blue metal door of the trailer in their faces. Frank, Joe, and Chet were obliged to turn away.

108 "Boy, was he angry!" said Chet as the three walked to their car. "Do you suppose he's in cahoots with his brother?"

Frank shook his head thoughtfully. "No. He was genuinely shocked at our story, that's all. Colonel Thunder still seems to be touchy about his family's honor.

Say, maybe our news will make him pay a call on his long-lost brother!"

"Yes, and maybe warn him of our suspicions," added Joe. "I suggest we sneak down into the hollow tonight and see what goes on."

"Good idea," Frank approved.

"Well, if it's all the same to you," put in Chet, "Mystery and old Chet will stay up in the cabin. I've had enough of that woods by night. Besides, after this morning's bit of detective work, I think I may say I've earned a rest."

"You have," Frank agreed, and Joe laughed. "Will we never hear the end of it?"

The three drove back to Forestburg. They stopped at the courthouse and learned from Sheriff Ecker that the prisoners had been sent under heavy guard to New Jersey, where Mr. Fenton Hardy, one of the chief investigators in the hijacking case, would question them.

"Is that a fact?" Frank asked mildly, giving Joe a wink.

"Yes, sir," Sheriff Ecker declared emphatically. "He's a real famous detective they called in on it. You boys ever hear of him?"

109 "Now and then." Joe grinned.

"Say, what are you two grinning about?" The sheriff frowned. "Hardy. Isn't that your last name, Frank and Joe? No relation, by chance?"

"Distant relation," Joe answered with a straight face. "About a hundred miles distant right now, I believe. He's our father."

"Well, I'll be . . ." Words failed the stocky, good-natured sheriff for a moment. Then his face became serious again. "And what about your friend, boys?

Hasn't come back yet, has he?"

Joe, about to pour out their suspicions of Walter Donner, was stopped by a nudge from Frank. "No, Sheriff," Frank replied, "but we're working on it.

We'll let you know if anything turns up."

After one final stop in Forestburg at Ciller's General Store for more 37 provisions, Frank, Joe, and Chet at last climbed into the captain's old car for the trip back to Black Hollow.

"Why not tell the sheriff about Donner's being a dognaper?" Joe asked as he drove.

"Because we still have to prove ourselves to Sheriff Ecker," Frank answered grimly. "Walter Donner made us look pretty incompetent in front of the sheriff. Any accusation we bring against him is going to need plenty of proof-no matter who our father is. Wait till we've really got the goods on Donner. Then we'll show the sheriff!"

To prepare for their long vigil that evening, 110 the brothers lay down for a nap as soon as they reached Captain Maguire's cabin. At sundown they were awakened by Chet Morton, who had prepared an appetizing dinner.

"About time for the night shift," he called. "Don't forget to put on dark clothing."

Soon a clear, cloudless sky, in which the stars sparkled brightly, spread itself over Black Hollow.

"The moon isn't due to rise until very late," Frank noted as the brothers prepared for their expedition. "That gives us an advantage since we're doing the spying."

A moment later, alert and refreshed by their sleep and fortified by Chet's meal, Frank and Joe slipped out the back door of the little cabin. As soon as their eyes became accustomed to the darkness, they entered the woods.

By now the path into the mysterious hollow was familiar to them even at night.

They moved along the trail noiselessly but swiftly, without flashlights.

Frank noted that it was the first time he had not had the eerie feeling of being followed in the woods.

"I suppose it's because we're in a position to do the following ourselves," he thought with a smile.

The boys avoided the exposed parts of the trail entirely, moving among the denser trees instead.

111 At length they reached the little clearing where Donner's strange cabin stood.

In the complete darkness they could see nothing but an indistinct ma.s.s of rocks and logs in front of them. The little building was invisible, except for a thin orange line of light around the frame of the closed door.

Cautiously Frank led the way as close as possible to the door without exposing themselves to the view of anyone else who might be in the surrounding woods.

They found a suitable place and stopped to listen. The sound of voices came to them plainly from inside the cabin-Walter Donner's voice, somewhat subdued, and the thin, whining voice of Wyckoff Webber, the attorney! The Hardys were astounded.

"I tell you, I've been to see Elizabeth," Webber was saying, "and she won't budge an inch."

There was a sound as of somebody moving a chair impatiently.

"Well"-Donner's big voice rumbled-"I'm fed up with this life. Fed up with it.

I want my share of the estate!"

"You don't think I'm fed up with it?" the lawyer replied irritably. "I want my money, too. Well, let's get down to business. How are things going?"

When they heard this question, Frank and Joe waited breathlessly for an answer. But none 112 came. There was a further sc.r.a.ping of furniture. That was all.

"Didn't Donner reply?" Frank wondered. "Or is he showing Webber something?"

While the young sleuth pondered, crouching in the dark, the sudden pressure of his brother's hand roused his attention. Now Frank heard the sound of stealthy footsteps approaching through the woods along the path!

From their hiding place Frank and Joe could easily watch the break in the woods where the path entered the clearing. But though they waited soundlessly, 38 no figure appeared. A chill of suspense ran down the brothers' spines.

"Is it Colonel Thunder?" Joe asked himself. "Or Simon?" Meanwhile, no further sound came from within the little house, either.

For about fifteen minutes the silence continued. The unknown intruder was no longer moving, but, the boys wondered, was he lurking in the darkness a few scant yards from the Hardys themselves?

"Somebody has trailed us down here," Joe thought uneasily, "and he's waiting for us to make the first movel"

CHAPTER XIV.

Flash Fire without changing his position, Joe moved enough so he could whisper to his brother.

"Somebody watching us," he murmured. "Waiting for us to show ourselves!"

Frank, after considering a moment, placed his own lips close to Joe's ear and replied: "Check! We'll outwait him."

Straining their eyes vainly against the darkness, Frank and Joe examined the break in the woods which marked the exit from the path. All they could make out, however, was the dark clump of bushes where the intruder must be hidden.

Whoever he was, he was keeping just as still and silent as they were!

Abruptly, the loud voices of Donner and Webber in the cabin could be heard once more. Their remarks were no longer m.u.f.fled.

113.

114 "We'll get some money pretty soon," Donner's voice rumbled. "I'm desperate enough to take a chance."

After a pause, Webber's irritable tones were heard in reply, "I'll attend to the boys. Nothing can go wrong this time!"

Hearing these words, Frank frowned to himself, puzzled. Were he and Joe and Chet "the boys" that the two were talking about? Before the youth could make up his mind, there was a rusty squeaking sound, and the door of the cabin was thrown open.

For an instant the lawyer's small, plump figure and Donner's tall, commanding one were outlined against the light of the two kerosene lanterns within. Then the door was closed and the lawyer crossed the clearing. He made no attempt to soften his footsteps.

Frank's keen eyes suddenly spotted an abrupt, blurred movement in the dark bushes at the entrance to the trail. Whoever was there was hiding from Webber as well as from them.

In another moment the lawyer had entered the woods. His footsteps quickly receded in the darkness. Still warily watching the bushes, Frank and Joe saw a man step out. For a moment he stood still, a dark form barely silhouetted against the faint glow of the starlight. Then soundlessly he entered the woods on the trail of the retreating Webber.

115 "He was spying on Webber!" Joe whispered. "Shall we tail the two of them and see what happens?"

"No," Frank decided quickly. "Let's stick to our plan of staying here and waiting for Colonel Thunder to show up."

Slowly, silently, the night wore on. The constellations changed their positions in the sky. In the east a pale glow appeared. At last a crescent moon showed itself above the trees. A light but chilly breeze sprang up.

Although the night was clear, the heavy early-morning dew of the mountains now covered everything. The boys' clothing, in particular their shoes and dungaree cuffs, was drenched from the long walk. Now the rest of their clothing felt damp and the cold breeze chilled them. Their legs were cramped from the long wait. They could see their breaths in the pale light thrown by the new moon.

No one else came to visit Walter Donner. At last the crack of light outlining the door of the little cabin could be seen no longer.

"I guess he's gone to bed," Frank whispered to Joe. "We may as well go back to 39 the cabin and hit the sack ourselves."

Using the same caution which they had practiced on the trek down, the two boys made their way through the dark woods to Captain Maguire's cabin. As they were climbing the steep, familiar 116 path out of the hollow, Frank suddenly laid a hand on Joe's arm.

"Listen!" he whispered.

From the depths of Black Hollow came an eerie sound, at first soft, then louder. It was a long, plaintive wail.

"Screech owl," Joe noted. "Where's it coming from?"