But they saw nothing of the two villains.

They had made good their escape.

Mr. Dalton stood by the rock, trembling and anxious, and after a few moments of silence, he asked, eagerly:

"Who is that?"

"Friends," cheerily replied Harry.

"Thank Heaven for that!"

"Harry, the villains are gone."

"Can you see how they got out?"

"Yes. There's another tunnel."

"Let them be for the present, and help me liberate this man."

"Wait till I get something from the other cave to break that chain."

He hastened back to the living room.

After the lapse of a few minutes he returned with a file.

While he was cutting open the padlock, Mr. Dalton asked:

"May I ask who you are, gentlemen?"

"The Bradys," replied Harry, quietly.

"What!" gasped the prisoner, in astonished tones.

"We've been hunting for you a long time, and found you at last."

"This is wonderful!"

"Perhaps to you, but not to us."

"For mercy's sake explain matters."

Harry complied as concisely as he could.

When he finished the old broker was thoroughly amazed at the great crime Mason committed in order to rob him.

That it was a failure was due to the detectives, he easily foresaw.

He thanked them again and again, and said, sadly:

"Poor Lizzie! She was faithful to me through all."

"No one will be gladder to see you than she," said Harry.

"And she's so near me now?"

"Yes. In a quarter of an hour you can be with her."

"I feel renewed hope now."

"Will you please tell us how your rascally nephew first managed to get you into his power, Mr. Dalton?" asked Harry, in curious tones.

"It was a very simple plan," replied the old broker. "He knew that I was going to get you to run down the thief who was robbing my mail. But he did not know that I suspected him of the crime. At any rate, on the night you mentioned, I had gone to the Union Club. A telegram reached me, saying you wished to see me at a house in Thirty-sixth street. I went there. Mason and my valet were waiting there for me. They attacked me. I shouted for help. They chloroformed me, bound and gagged me, put me in a box they had prepared for my reception, and--well, all became a blank."

"They had the box and wagon ready ahead, eh?"

"It was a prearranged plot," the broker replied. "That was evident. I came to my senses in the box, and realized that I was being carried off on a railway car. Then you opened the box. The next thing I knew, the box I was in was thrown from the car. The shock stunned me. When I recovered I found myself being carried over a swamp into a hut. The gag was off my mouth, and I shouted for help."

"Yes; we heard you."

"The negro who carried me brought me down here and secured me this way.

Then Mason made his appearance. For the first time I then learned that he was the author of all my trouble. He was bound to secure my bank balance, and I refused to sign a check so he could get it. Infuriated over my persistent refusal, he tortured and starved me. The rest you probably know."

"We heard all they said this morning."

Just then Old King Brady finished cutting the lock, and the man was free and able to walk.

He was very weak, though, and the detectives had to support him.

"Do you know anything about the pa.s.sage by means of which the villains escaped from here?" asked Old King Brady.

"Oh, yes. I've often explored this place," replied Mr. Dalton, readily.

"It's a pa.s.sage leading under the swamp to the mainland."

"Show us the way, and we will follow it."

"Come along, then, and in a few minutes we'll be out of here."

They entered the tunnel, and Old King Brady said to the broker:

"When I entered the Thirty-sixth street house the night you were abducted, I found a curious dagger lying on the floor, and blood-stains on the boards. These clews led me to suppose a murder had been committed there. Do you know anything about those things?"

"Yes," replied the broker. "The dagger was one I had purchased as a curiosity that evening from a shop in Fourth avenue. When those two men attacked me, I drew it, and cut the negro before they got the best of me by knocking it from my hand. Sim bound up his wound, and then they knocked me down and drugged me."

Old King Brady laughed.

"Another mystery solved," he muttered.

"You thought I was the victim, eh?"