"Now, dad, tell me all about it," requested Tom when he and Ned were in Mr. Swift's apartment at the hotel, safe from the rain that was falling. "How did you happen to see Anson Morse and Happy Harry?" My old readers will doubtless remember that the latter was the disguised tramp who was so vindictive toward Tom, while Morse was the man who endeavored to sneak in Mr. Swift's shop and steal a valuable invention.

"Well, Tom," proceeded the inventor, "there isn't much to tell. I was out walking in the woods yesterday, and when I was behind a clump of bushes I heard voices. I looked out and there I saw the two men."

"At first I thought they were trailing me, but I saw that they had not seen me, and I didn't see how they could know I was in the neighborhood. So I quietly made my way back to the hotel."

"Could you hear what they were saying?"

"Not all, but they seemed angry over something. The man with the blue ring on his finger asked the other man whether Murdock had been heard from."

"Who is Murdock?"

"I don't know, unless he is another member of the gang or unless that is an assumed name."

"It may be that. What else did you hear?"

"The man we know as Morse replied that he hadn't heard from him, but that he suspected Murdock was playing a double game. Then the tramp---Happy Harry---asked this question: 'Have you any clew to the sparkler?' And Morse answered: 'No, but I think Murdock has hid it somewhere and is trying to get away with it without giving us our share.' Then the two men walked away, and I came back to the hotel," finished Mr. Swift.

"Sparkler," murmured Tom. "I wonder what that can be?"

"That's a slang word for diamonds," suggested Ned.

"So it is. In that case, dad, I think we have nothing to worry about. Those fellows must be going to commit a diamond robbery or perhaps it has already taken place."

The inventor seemed relieved at this theory of his son. His face brightened and he said: "If they are going to commit a robbery, Tom, we ought to notify the police."

"But if they said that 'Murdock,' whoever he is, had the sparkler and was trying to get away with it without giving them their share, wouldn't that indicate that the robbery had already taken place?" asked Ned.

"That's so," agreed Tom. "But it won't do any harm to tell the hotel detective that suspicious characters are around, no matter if the has been committed. Then he can be on the lookout. But I don't think we have anything to worry about, dad. Still, if you like, I'll take a run down to the house to see that everything is all right, though I'm sure it will be found that we have nothing to be alarmed over."

"Well, I will be more relieved if you do," said the inventor, "However, suppose we have a good supper now and you boys can stay at the hotel to-night. Then you and Ned can start off early in the morning."

"All right," agreed Tom, but there was a thoughtful look on his face and he appeared to be planning something that needed careful attention to details.

After supper that night Tom took his chum to one side and asked: "Would you mind very much if you didn't make the trip to Shopton with me?"

"No, Tom, of course not, if it will help you any. Do you want me to stay here?"

"I think it will be a good plan. I don't like to leave dad alone if those scoundrels are around. Of course he's able to look after himself, but sometimes he gets absent minded from thinking too much about his inventions."

"Of course I'll stay here at the hotel. This is just as good a vacation as I could wish."

"Oh, I don't mean all the while. Just a day or so---until I come back. I may be here again by to-morrow night and find that my father is needlessly alarmed. Then something may have happened at home and I would be delayed. If I should be, I'd feel better to know that you were here."

"Then I'll stay, and if I see any of those men---"

"You'd better steer clear of them," advised Tom quickly. "They are dangerous customers."

"All right. Then I'll go over and give Miss Nestor lessons on how to run a motor-boat," was the smiling response. "I fancy, with what she and I know, we can make out pretty well."

"Hold on there!" cried Tom gaily. "No trespassing, you know."

"Oh, I'll just say I'm your agent," promised Ned with a grin. "You can't object to that."

"No, I s'pose not. Well, do the best you can. She is certainly a nice girl."

"Yes, but you do seem to turn up at most opportune times. Luck is certainly with you where she is concerned. First you save her in a runaway---"

"After I start the runaway," interrupted Tom.

"Then you take her for a ride in your motor-boat, and, lastly, you come to her relief when she is stalled in the middle of the lake. Oh you certainly are a lucky dog!"

"Never mind, I'm giving you a show. Now let's get to bed early, as I want to get a good start."

Tom awoke to find a nasty, drizzling rainstorm in progress, and the lake was almost hidden from view by a swirling fog. Still he was not to be daunted from his trip to Shopton by the weather, and, after a substantial breakfast, he bade his father and Ned good-by and started off in the Arrow.

The canopy he had provided was an efficient protection against the rain, a celluloid window in the forward hanging curtains affording him a view so that he could steer.

Through the mist puffed the boat, the motor being throttled down to medium speed, for Tom was not as familiar with the lake as he would like to have been, and he did not want to run aground or into another craft.

He was thinking over what his father had told him about the presence of the men and vainly wondering what might be their reference to the "sparkler." His thoughts also dwelt on the curious removal of the bracing block from under the gasoline tank of his boat.

"I shouldn't be surprised but what Andy Foger did that," he mused. "Some day he and I will have a grand fight, and then maybe he'll let me alone. Well, I've got other things to think about now. The hotel detective can keep a lookout for the men around the hotel, after the, warning I gave him, and I'll see that all is right at home."

The fog lifted somewhat and Tom put on more speed. As he was steering the boat along near shore he heard, off to the woods at his right, the report of a gun. It came so suddenly that he jumped involuntarily. A moment later there sounded, plainly through the damp air, a cry for help.

"Some one's hurt---shot" cried the youth aloud.

He turned the boat in toward the bank. As he shut off the power from the motor he heard the cry again:

"Help! Help! Help!"

"I must go ashore!" he exclaimed. "Probably some one is badly wounded by a gun."

He paused for a moment as the fear came to him that it might be some of the patent thieves. Then, dismissing that idea as the Arrow's prow touched the gravel, Tom sprang out, drew the boat up a little way, fastened the rope to a tree and hurried off into the dripping woods in the direction of the voice that was calling for aid.