Penny and Rosanna approached the mine entrance cautiously, fearing that someone in the vicinity might observe their movements. However, the place seemed deserted.

“The rowboat is gone,” Penny commented as she pulled aside a clump of bushes to survey the spot where it had been hidden.

“Why, it is! Perhaps the ghost has come and left.”

“I certainly hope not. That would ruin everything. Anyway, we’ll wait and see. It’s early yet.”

After investigating the shore line thoroughly, they found an excellent hiding place in a dense thicket not far from the entrance to the mine. Then they settled themselves to wait.

“What time is it?” Rosanna yawned.

“Only a little after nine. We’ll have a long siege of it.”

The night was cold and damp. Although both girls had worn sweaters they soon grew uncomfortable and huddled close together for warmth. Rosanna tried not to show her nervousness but even the screech of an owl startled her. She was aware of every sound and any unusual movement caused her to grow tense.

“You’ll be a wreck long before midnight,” Penny declared. “We’re armed and there’s nothing to fear.”

Rosanna made a supreme effort to relax but it was not until several hours had elapsed that she began to grow accustomed to her surroundings. Penny, on the other hand, found it difficult to remain awake.

At first she riveted her attention upon the lake but as there was no evidence of a boat, soon lost interest. For a time she watched the twinkling lights at Raven Ridge but one by one they disappeared until the old mansion on the hill was cloaked in darkness.

“Now that the household has gone to bed our ghost should be starting in on his night’s work,” she remarked hopefully to Rosanna.

Another half hour dragged by. Still no one came. Even Rosanna found it increasingly difficult to fight off drowsiness.

“I don’t believe the ghost is coming tonight,” she declared.

“It begins to look that way. But perhaps it’s still too early. Surely it can’t be any more than midnight.”

“It seems later than that,” Rosanna sighed. “My back is nearly broken.”

A few minutes later, from far over the hills, the girls heard the faint chiming of a town clock. They counted twelve strokes.

Minutes passed and still there was no sign of any visitor. At length, Penny arose to stretch her cramped limbs.

“I thought I heard something just then!” Rosanna whispered tensely.

Penny stood listening.

“You’re right. I can hear oars dipping in and out of the water. It must be a boat coming this way.”

Peering out through the bushes, the girls surveyed the lake. It was too dark to distinguish objects but they distinctly could hear the rhythmical splash made by the moving oars.

“See anything?” Penny demanded.

“Not yet oh, yes, now I do. It is a boat, Penny.”

“And it’s heading right for this spot! Let’s creep a little closer to the opening of the tunnel.”

Stealthily they changed positions but remained well hidden by a screen of bushes.

The boat by this time had drawn into the tiny cove. However, the night was so dark that neither of the girls was able to distinguish the features of the man who crouched in the stern.

He beached the boat and carefully drew it up into the bushes. Next he lighted a lantern, but his back was toward the girls and they did not see his face.

“Who can it be?” Rosanna whispered.

Penny gripped her companion’s hand as a warning to remain silent.

The man with the lantern looked quickly about and then moved swiftly into the mouth of the tunnel.

“We must follow him,” Penny urged.

They waited a minute, then noiselessly stole from their hiding place. As they peered into the dark mine tunnel they could see a moving light far ahead.

Fearing that they might lose sight of the man, the girls hastened their steps. They did not walk as quietly as they imagined, for soon the man ahead paused.

With one accord Penny and Rosanna froze against the tunnel wall.

As the man turned to look back, the light from the lantern shone full upon his face.

It was Caleb Eckert.

Rosanna and Penny remained flat against the wall scarcely daring to breathe. Would they be seen?

Apparently satisfied that no one was behind him in the tunnel, Caleb turned and walked slowly on.

“That was a narrow escape,” Penny whispered. “He nearly saw us.”

Rosanna was a trifle shaken. She had not expected to see Caleb Eckert.

“I suspected it several days ago but I wasn’t absolutely certain,” Penny told her.

“But what purpose can he have in playing such pranks?” Rosanna asked in bewilderment. “Caleb seemed rather nice even if he was gruff and outspoken. I never dreamed he’d resort to anything like this.”

“Don’t take it so hard,” Penny advised. “He may have a reason for what he is doing.”

The light had disappeared. The girls hurriedly moved on, fearing that they might lose sight of the old man entirely. With nothing to guide them it was difficult to find their way.

“It’s lucky we explored in the daytime or we’d have trouble following,” Rosanna declared. “The ground is so rough.”

Even as she spoke she stubbed her toe on a rock and would have fallen had not Penny caught her by the arm.

They came presently to the first flight of stairs and were relieved to glimpse the lantern far above them. Taking care to keep out of range of the beam, they followed through the narrower passage to the second flight of steps.

By this time the girls were positive that Caleb intended to enter the house by means of the secret panel. At the risk of detection they drew a little closer.

Caleb paused at the head of the stairs to listen for a moment. Then he blew out his lantern.

Sensing that the old man would unlock the panel, Penny stole forward. She was just in time to see a section of the wall drop down. Caleb passed through the opening and with a click the panel closed behind him.

“Now what shall we do?” Rosanna demanded. “We’re locked in here the same as we were before.”

“I think I saw the place where he pressed the wall,” Penny whispered. “I was watching closely.”

For several minutes she groped about in the dark. At last her fingers touched a small knob.

“I believe I’ve found it,” she proclaimed triumphantly.

As she was on the verge of turning the knob, she stayed her hand. With Caleb in the organ room he would be certain to see the panel open. There was danger too that he might return at any instant to find them crouching at the head of the stairs.

“Shouldn’t we turn back?” Rosanna whispered nervously.

“Let’s wait until he begins to play the organ.”

They listened expectantly. Minutes passed but not a strain of music did they hear.

“That’s queer,” Penny murmured. “I’m sure Caleb is the one who has been disturbing the household with his ghost music. Why doesn’t he play as he’s always done before?”

They both knew that the wall was not soundproof. For that matter they could hear old Caleb walking about in the room.

“He must be up to new tricks tonight,” Penny whispered.

“He’ll be coming back here any minute. Let’s get away before he catches us.”

Penny was reluctant to leave, for it struck her that Caleb Eckert had come to the Winters’ house for a different purpose than that of his usual nightly visit. She was curious to learn what it was.

“Listen!” she warned, as they heard a strange noise from within.

“It sounded like a door closing,” Rosanna declared.

“That’s exactly what I think it was. Caleb must have gone out of the room. We’ll be safe in entering now.”

To make certain she listened for a few minutes but there was no sound of movement from within. Convinced that the coast was clear, she groped about for the knob which opened the panel.

It turned in her hand. She heard a sharp metallic click, and almost before she was prepared for it, the panel swung open. It closed again before either of the girls could recover from their surprise.

However, Penny turned the knob a second time and as the section of wall swung back, both girls stepped through into the room.

As they had expected, it was deserted.

“Where do you suppose he went?” Rosanna murmured.

They tiptoed to the outside door and softly opened it. The hall was dark. At first they could distinguish nothing. Then Penny noticed that the door opening upon the second floor corridor was ajar.

“He went downstairs,” she whispered. “Let’s find out what he’s up to.”

The stairs creaked alarmingly as they crept down to the second floor. On the landing they hesitated an instant and were relieved to hear no unusual sound.

They peered into the long corridor and saw that it was empty. Caleb was nowhere to be seen.

“Perhaps he brought another bat for Mrs. Leeds’ room,” Rosanna suggested, glancing toward the chamber which the woman shared with her daughter.

The door, however, was tightly closed. The one at the other end of the hall which opened into Max Laponi’s room was slightly ajar. Rosanna and Penny failed to notice.

Somewhere on the lower floor a board creaked. The two girls moved noiselessly to the stairway and looked down over the banister.

Even Penny was unprepared for the sight which greeted her eyes. Caleb Eckert was working at the dials of the living room safe!