Tom Swift, for the moment, did not know what to do. It was a strange situation, and one he had never thought of. What did the mysterious message mean? He must think it all out, and plan some line of action. Clearly Mrs. Damon was not able to do so.

"Now let's get at this in some kind of order," suggested the youth, when Mrs. Damon had calmed herself. It was his habit to have a method about doing things. "And don't worry," he advised. "I am certain some good will come of this. It proves one thing, that's sure."

"What is it, Tom?"

"That Mr. Damon is alive and well. Otherwise the message would not have said he would be 'released.' It wasn't from anyone you know; was it?"

"No, I'm sure I never heard the voice before."

Tom paused a moment to think how useful his photo telephone and phonograph arrangement might have been in this case.

"How did the telephone call come in?" inquired the young inventor.

"In the usual way," answered Mrs. Damon. "The bell rang, and, as I happened to be near the instrument, I answered it, as I often do, when the maid is busy. A voice asked if I was Mrs. Damon, and of course I said I was. Then I heard this: 'Sign the land papers, and send them to us, and your husband will be released.'"

"Was that all?" Tom asked.

"I think so--I made a note of it at the time." Mrs. Damon looked into a small red book. "No, that wasn't all," she said, quickly. "I was so astonished, at hearing those strange words about my husband, that I didn't know what to say. Before I could ask any questions the voice went on to say, rather abruptly: 'We will call you again.'"

"That's good!" cried Tom. "I only hope they do it while I am here. Perhaps I can get some clue as to who it was called you. But was this all you heard?"

"Yes, I'm sure that was all. I had forgotten about the last words, but I see I have them written down in my note book."

"Did you ask any questions?" inquired Tom.

"Oh, indeed I did! As soon as I got over being stunned by what I heard, I asked all sorts of questions. I demanded to know who was speaking, what they meant, where they were, and all that. I begged them to tell me something of my husband."

"And what did they say?"

"Not a thing. There wasn't a sound in the telephone. The receiver was hung up, breaking the connection after that message to me-- that mysterious message."

"Yes, it was mysterious," agreed Tom, thoughtfully. "I can't understand it. But didn't you try to learn from the central operator where the call had come from?"

"Oh, yes, indeed, Tom! As soon as I found out the person speaking to me had rung off, I got the girl in the exchange."

"And what did she say?"

"That the call came from an automatic pay station in a drug store in town. I have the address. It was one of those telephones where you put your money for the call in a slot."

"I see. Well, the first thing to do is for me to go to that drug store and find out, if I can, who used the telephone about that time. It's a slim chance, but we'll have to take it. Was it a man's voice, or a woman's?"

"Oh, a man's, I'm sure. It was very deep and heavy. No woman could speak like that."

"So much is settled, anyhow. Now about the land papers--what was meant?"

"I'll tell you," said Mrs. Damon. "You know part of our property-- considerable land and some buildings--is in my name. Mr. Damon had it fixed so a number of years ago, in order to protect me. No one could get this property, and land, unless I signed the deeds, or agreed to sign them. Now all of Mr. Damon's fortune is tied up in some of Mr. Peters's companies. That is why my husband has disappeared."

"He didn't disappear--he was taken away against his will; I'm positive of that!" exclaimed Tom.

"Perhaps so," agreed Mrs. Damon, sadly. "But those are the papers referred to, I'm sure."

"Probably," assented Tom. "The rascals want to get control of everything--even your possessions. Not satisfied with ruining Mr. Damon, they want to make you a beggar, too. So they are playing on your fears. They promise to release your husband if you will give them the land."

"Yes, that must be it, Tom. What would you advise me to do? I am so frightened over this!"

"Do? Don't you do anything!" cried Tom. "We'll fool these rascals yet. If they got those papers they might release Mr. Damon, or they might not--fearing he would cause their arrest later. But we'll have him released anyhow, and we'll save what is left of your fortune. Put those land papers in a safe-deposit box, and let me do the rest. I'm going to catch those fellows!"

"But how, Tom? You don't know who they are. And a mere message over a telephone won't give you a clue to where they are."

"Perhaps not an ordinary message," agreed Tom. "But I'm going to try some of my new inventions. You said they told you they were going to call again?"

"That's what they said, Tom."

"Well, when they do, I want to be here. I want to listen to that message. If you will allow me, I'll take up my residence here for a while, Mrs. Damon."

"Allow you? I'll be only too glad if you will, Tom. But I thought you were going to try to get some clue from the drug store where the mysterious message came from."

"I'll let Ned Newton do that. I want to stay here."

Tom telephoned to Ned to meet him at Mrs. Damon's house, and also to bring with him certain things from the laboratory. And when Ned arrived in an auto, with various bits of apparatus, Tom put in some busy hours.

Meanwhile Ned was sent to the drug store, to see if any clues could be obtained there as to who had sent the message. As Tom had feared, nothing could be learned. There were several automatic 'phones in the place, and they were used very often during the day by the public. The drug clerks took little or no notice of the persons entering or leaving the booths, since the dropping of a coin in the slot was all that was necessary to be connected with central.

"Well, we've got to wait for the second call here," said Tom, who had been busy during Ned's absence. He had fitted to Mrs. Damon's telephone a recording wax phonograph cylinder, to get a record of the speaker's voice. And he had also put in an extension telephone, so that he could listen while Mrs. Damon talked to the unknown.

"There, I guess we're ready for them," said Tom, late that afternoon. But no queer call came in that day. It was the next morning. about ten o'clock, after Mrs. Damon had passed a restless night, that the telephone bell rang. Tom, who was on the alert, was at his auxiliary instrument in a flash. He motioned to Mrs. Damon to answer on the main wire.

"Hello," she spoke into the transmitter. "Who is this?"

"Are you Mrs. Damon?" Tom heard come over the wire in a deep voice, and by the manner in which Mrs. Damon signalled the young inventor knew that, at the other end of the line, was the mysterious man who had spoken before.