"It's too valuable to leave, and it won't take up much room. Come on, and pick up what we can. The fewer trips we make, the better it will be for us. Come on."

The light flickered and the footsteps of the men died away.

"I say Jack!" called Walter, after a moment's pause.

"Yes, what is it?"

"What's the matter with our going outside and getting Cora's auto now.

It's got a lot of their stuff in it that will be fine for evidence against them. It's our best chance-just slip out now and get Cora's car."

"That's right," agreed Paul. "If we let them get away with it again we may never see it."

"All right," agreed Jack. "You two go out and capture the car. Do whatever you think best about it. I'll stay here and follow the men when they come out. If they have some of their machinery that will be additional evidence against them. Go ahead."

Paul and Walter hurried out, leaving Jack alone in the dark cave. They left him the lantern, saying they could find their way out by means of matches. Jack felt a little apprehensive as he was left alone, knowing that at least three men, who might prove desperate criminals, were in the cave with him. And if they discovered him, and knew that he was one of those working against them-well, Jack did not altogether like to speculate on what might follow.

Those seeking to solve the mystery were now divided into three parties.

There was Jack, alone in the cave, waiting for the return of the three men. Walter and Paul were on their way outside to get the automobile.

While Cora and her chums were prisoners of the old man and his imbecile son.

Walter and Paul reached the outer end of the cave without incident, and just without the wooden shack found Cora's car standing unguarded and well-laden with packages and some small bits of machinery.

"Caught with the goods!" chuckled Paul. "This game is coming right into our hands now. What shall we do?"

"Drive the car as near to the bungalow as we can," decided Walter. "The girls will be anxious about us, anyhow. We can leave the car with Mr.

Floyd and then come back to Jack."

A quick examination showed that Cora's car, though it had been sadly misused, was in shape for running. It responded at once to the self-starter and Walter and Paul were soon chugging down the road, taking off the spoils of the ticket counterfeiters.

"Camp Surprise ahoy!" called Walter as he ran the car as near as he could to the bungalow. "Girls, where are you? We've got great news!

We've solved the mystery!"

There was no answer to the hail, and Paul looked at his chum rather apprehensively as they alighted.

"They don't seem to be here," he said.

"They must be," Walter argued. "There's Mrs. Floyd. We'll ask her."

"Why, aren't the girls in the bungalow?" asked the chaperon, wonderingly. "I have been away a little while, and just got back. They were here when I left."

A quick search through the bungalow failed, of course, to disclose the presence of Cora and her chums. The entrance to the secret pa.s.sage was still open, but Walter, running down the steps, reported that the girls were not there, and that the blocking door was closed.

"But we'll soon have it open," he said. "We have permission from Mr.

Haight to tear down the obstruction."

"Where is Mr. Kimball?" asked Mr. Floyd, who had been summoned by his wife from a bungalow not far away, where he was making some repairs.

"He's up in the cave, keeping watch on the counterfeiters," said Paul.

"It's a great story!"

Thereupon he and Walter gave a short account of the movements of themselves and Jack up to the present.

"But where are the girls?" asked Paul. "We must find them."

"Perhaps they went up to the cave Cora found," suggested Walter. "Let's go there and look."

"First we'd better see if Jack doesn't need help," Paul said. "I guess the girls know enough to keep out of danger, and it's daylight yet.

We'll go to Jack."

"I'll take charge here," said Mr. Floyd. "I've got a man working with me at the other bungalow, and he and I will stand guard over the auto. When you come back, if the girls haven't returned, we'll go after them."

This plan was deemed the best to follow, and Paul and Walter hastened back on foot to the cave where they had left Jack.

Cora and her friends, made prisoners in the cave by the old man and his horrible, grinning, half-witted helper, felt faint and sick as they realized what might be the outcome. For a moment none of them spoke. The old man laughed, showing his blackened teeth-a strange contrast to his white beard-and then he chuckled:

"Police spies; eh? Come to catch the old man! But he was too smart for ye; wasn't he? He caught you; didn't he?"

"What do you mean by locking us in?" demanded Cora. "Open that door at once and let us go!"

"And call away that-that horrid idiot!" half-sobbed Belle. "If he catches hold of me--"

"Oh, Bombee won't hurt you; will you, Bombee?" said the old man, patting the half-witted youth on the head. "That is, he won't if you do as I say, and don't try to run. Bombee's like a dog. He's my pet, so he is.

Hi, Bombee! Do a trick for the ladies!"

The idiot gave a shrill cry, bounded up on a box and stood on his head, his legs kicking in the air.

"See!" chuckled the old man. "Bombee minds me. If I was to tell him to bite you he would, but I won't tell him."

"You let us go!" demanded Cora, her thoughts in a whirl with the strange ideas that came to her mind.

"I didn't ask you to come here," snapped the old man. "And them as comes uninvited must stay until they're let go. Ye can't go out and bring in the police."

"But if-if we promise not to tell the police?" faltered Bess.

"I wouldn't trust you," snarled the old man.

"Then there must be something here about which you are afraid," said Cora, boldly. "Why do you fear the police?"

The man gave her a sharp glance.

"Never you mind that," he said. "When the others come I'll know what to do with you. I'll make you--"

He paused and seemed to be listening. At the same time the idiot gave a whimpering cry.

"Some one's coming!" snarled the old man. "The police, maybe. You've sent 'em. But they won't find you. Quick, Bombee-the secret room-open the door!"

The half-witted creature bounded forward, and caught up a club. Bess screamed, fearing the fellow was going to attack them. But the idiot merely put the stick in a hole in the wall, and pressed on the lever with all his might. A heavy plank door swung out, revealing a black room.

"Into that with you!" cried the old man.