"Meet her, and I will wager that there will be some of her gang hovering around. We can play a very ingenious trick and open up their scheme."

"How will you do it?"

"I can make up for you."

"You can do it perfectly."

"To-night I will go to meet this siren."

"No, no, I will meet her."

"Yes, you shall meet her, but listen: I will go to meet her; you will be on _my_ track. You will see who will follow me, believing that they are following you. We can arrange where, at a given point, I will disappear and you will reappear, and then when you go to meet this siren you will know just exactly how the ground lays. You will have the whole business down on them."

"Cad, this is a great scheme."

"It is, if we play it out right. This girl will be working you for an innocent; you can afford to give her a great deal of information, and--"

The girl stopped short.

"Go on," said Oscar, "what will you be doing?"

"Why, man, between us, matching them at their own game, we will get the ident.i.ties of every member of the gang. We will learn where their shops and where their plates are."

"How will we do it?"

"We will know just whom to shadow for each separate bit of information."

"By ginger! you are right."

"Now that you are up to this siren's movements I can trust you, Oscar."

"I might have gotten on to her plans. I was not about to surrender on demand, but it is better as it is. Time is saved, and to-night we will work our scheme. You shall be Oscar; I will be Cad, and at the proper moment we will resume and let the game go on."

"That is my idea."

That night at the proper hour an individual who looked very much like Oscar might have been seen hovering in the vicinity of the restaurant where the interview between the detective and the siren was to take place.

Our readers can grasp what was going on. Oscar, gotten up as a female, was on the "shadow," and very speedily all that Cad Metti had told him was confirmed. He saw two men following his talented counterfeit, and he followed them, and at the proper moment rejoined Cad. The second change was made and Oscar proceeded to the restaurant to meet the siren. He found her at the appointed place, and together they entered the dining-room and took seats at the same table where they had held their original consultation. The woman appeared to be in excellent humor and said:

"Oh, I feel so greatly encouraged."

"I will encourage you still further. I have considered the matter and I have determined to rescue your brother, but I must have your full confidence. What is your name?"

"Libbie Van Zant."

"Very well, Miss Van Zant, when am I to meet your brother?"

"You are not to meet him right away."

"Why not?"

"I do not wish him to suspect that I have betrayed him. I must have time to prepare him for the meeting with you."

"That is all right."

"And now let me tell you something: these are very desperate men; you must secure aid."

"Oh, certainly."

"I want you to select the men who will aid you. We must not make a mistake. You must have men with you when you make the raid on the place."

"I certainly will."

"Will you introduce them to me?"

"Why should I introduce them to you?"

"I wish to know them, so I can arrange for my brother's safety."

"Oh, I see; well, in good time you shall meet them."

"We must go slow and sure in this matter."

"Oh, certainly, and you are becoming quite a detective."

"I am working for my brother's safety--his salvation. I am willing to brave almost everything to save him."

"We will save him."

"By to-morrow I will arrange for my brother to have a meeting with some of those men with whom he is a.s.sociated, and I will arrange that you shall be hidden in a place from where you can overhear everything that is said. You will secure considerable information. You will know how to use it. Yes, we will move slowly, but surely. There must be no mistake made, no failure, or it will cost my brother's life, and I also may become their victim."

"Very well, you can depend upon me."

"I have your confidence?"

"Yes."

"Can we not arrange signals between us?"

"Certainly."

"I am going to start in as a regular detective in this affair, and at any moment I may want to signal to you; yes, warn you in case anything appears to be going wrong at a critical moment."

"I am delighted to work with one as shrewd and thoughtful as you are,"

said Oscar.

"Can you not come to my home to-morrow?"

"I fear I will not have time."