Forrester's splendid health, and the prompt treatment he had received, quickly put him on his feet. The second day after his adventure he had sufficiently recovered to drive home in his car. This had been placed in the Bradbury barn by Joshua, who also completed the exchange of tires, which had been interrupted.

The effect of this incident upon his family worried Forrester. It would drive his mother into a state of hysterical fear that could not fail to seriously impede his investigations. When he mentioned this phase of his accident to Mary Sturtevant, however, he found that the clever and resourceful girl had foreseen and provided against such an occurrence.

Green had been summoned shortly after Forrester was brought to the house, the attack explained and instructions given to inform Forrester's family that a business proposition had called him away unexpectedly for a few days.

"No one outside of Mr. Green and my servants will ever know of this incident," Mary Sturtevant informed Forrester, "if you remain silent. And for my sake I know that you will."

Forrester promised, though strange doubts and misgivings battled with his affection for the girl. But of what use was love, he reflected, if it could not stand the fire and acid tests of life's problematical moments. That the girl loved him he did not question now. It was only this dark and fearsome mystery which continued to hold them apart.

Back home again, Forrester bathed and changed his clothes; then, after looking up his mother and sister and accounting for his absence in a matter of fact manner, he sought Green at his station in the pergola.

"Narrow escape, Mr. Forrester," commented Green, as Forrester shook hands with him and sat down. "Funny how that Miss Sturtevant happened to be so handy. What do you say?"

"I came out to have a talk with you, Green, along that line," replied Forrester. "I have found some of your ideas right to the point. In other ways you don't seem to get anywhere. Now, for example, your surmise about the Italians was correct. Your theory that Lucy is not connected with these people appears to be confirmed by the investigations of the police. The position you take that the 'Friends of the Poor' are located in the vicinity of the tree grows stronger every day. But—you don't seem able to point your finger at a single person or thing that will give us a solid basis upon which to work. That is what I want now—a real suggestion that I can follow up, and through which I may hope to form some definite conclusion or take positive action. We must have action, Green; quick action."

"I have given you a valuable hint, Mr. Forrester, but you turned it down. What about them two people I saw on Prentice's lawn—what about the man who visited Miss Sturtevant and then hid himself behind the tree and pulled out your package while the excitement was on—what about 'em, eh? Why, damn it all!" Green exclaimed, jumping to his feet and pounding a big fist on the palm of his open hand, "just let me get out of here and I'll show you somethin'. How can I get anywhere, just sittin' here communin' with the birds. If you won't let me do it, then get out yourself and find that man. Between him and the girl you got two startin' points that'll bag the whole crew."

Forrester sat in silence after this outburst. Green was right! The detective had pointed an accusing finger at Mary Sturtevant. He had given Forrester positive information that she knew something definite about the "Friends of the Poor," and yet, blinded by his infatuation, Forrester had done nothing.

"All right, Green," agreed Forrester, "I'll work on your suggestions. How can we locate that man, however?"

"If he had a date with her once, he'll have another," asserted Green. "Stick around—that's all. That girl'll solve the case for you yet. Just get her in a tight corner." Then he leaned down to Forrester and added, in a low, confidential tone, "And don't forget that old story about them sireens on the rocks."

A few days later Forrester met Mary Sturtevant at a dance. Though he had promised Green that he would watch her, Forrester had dallied over taking the first step. Now, as he chatted with her and felt the spell she always cast over him, Forrester's whole being revolted at the thought of spying upon her.

"Do you wish any dances?" she inquired, after a time. Forrester's face flushed. Divided between his disturbing reflections and the enchantment of her nearness, he had not thought of reserving any dances. He held out his hand and she placed her dance card in it.

"You see, you are always late," she chided him. "Five dances are already taken."

"I'll take these three after young Melville," announced Forrester, and wrote his initials on the card.

Forrester had lost his interest in dancing of late, so he held himself in the background until it was time to claim his first dance with Mary Sturtevant. Then he hunted for her everywhere. She was not to be found, and even after the orchestra had begun to play, she did not appear. He saw nothing further of her until time for his second dance, when he suddenly became aware that she was standing by his side.

"You are like the beautiful young woman that the magician passes through his cabinet," exclaimed Forrester.

"Do I appear and disappear so mysteriously as all that?" she laughed, but offered no apology nor explanation.

Then the music began and they swept out on the floor.

Just before the dance ended Forrester noted a stir near the conservatory doors. Though the doors were closed, several people were grouped about them, apparently looking through the glass at something going on within the conservatory. When the music stopped Forrester suggested that they stroll in this direction and ascertain what was taking place. Before they reached the conservatory doors, however, Mr. Melville, their host, appeared at Forrester's side. The man's face was pale and drawn.

"Forrester," said Mr. Melville in a low voice, "we have had an accident in the conservatory. I would appreciate your help. Come around by way of the hall—the doors from this room have been locked."

Mr. Melville turned away toward the hall and Forrester excused himself to Mary Sturtevant. He noticed that her face also had paled.

"I think I know what has happened," she said. "Please let me go with you."

"It might not be agreeable to Mr. Melville," objected Forrester.

"Robert," she whispered, impressively, "you are safe only when I am with you!"

Forrester stared at her in astonishment. There was a beseeching look in her eyes, however, and she held her hands out to him with a pleading gesture which he could not resist.

"Come," he said, briefly, and taking her arm led her across the room and around through the hall into the conservatory. Near its center, hidden from prying eyes among palms and flowering plants, they found Mr. Melville's son stretched out on a bench. Near by stood the father, while a gray-haired man leaned over the young man. The gray-haired man stood erect at the sound of Forrester's and the girl's approach. Mr. Melville was apparently too much distressed to notice Mary Sturtevant's unbidden presence. He turned to Forrester, informing him simply that the gray-haired man was a doctor.

The deathly pallor on the young man's face told the story. Forrester, however, inquired:

"Dead?"

"Yes," replied the doctor. "Asphyxiated!"

"This is the work of the 'Friends of the Poor,' Forrester," asserted Mr. Melville. "I knew that you were involved and had been carrying on some investigations in the matter. It occurred to me that there might be some clues here of value to you. This is the story:

"About two weeks ago I was ordered by these people to place a certain sum in that oak tree. Naturally, I ignored the demand and notified the police. Since then I have taken every precaution to protect myself against attack. Unable to get at me, it seems obvious that these contemptible wretches have reached me through my son. That, I believe, is a new angle, and shows the extremes to which these people are prepared to go."

"When did this happen, Mr. Melville?" asked Forrester.

"About a half-hour ago, I should say, I saw my son pass into the conservatory with this young lady," and Mr. Melville turned toward Mary Sturtevant for the first time.

Forrester also turned and looked at the girl. She met his gaze steadily.

"Shortly after I came here," she explained, "my next dancing partner entered and claimed me. I left young Mr. Melville sitting near that open window over there."

Forrester gave no outward indication of the shock he had received. He clearly remembered that after young Melville's dance the next three dances were his. It was during the first of these, the one she had intimated belonged to someone else, that he had missed the girl. He knew, therefore, that she had lied deliberately, placing it squarely up to him to protect her. "Protect her from what?" thought Forrester. "What was this frightful new development in the mystery?"

"I decided I wanted a smoke," continued Mr. Melville, "and so came into the conservatory. A moment later I found my son on the floor beneath that open window where Miss Sturtevant says she left him. My doctor was among the guests and I summoned him at once—but too late, it seems."

"Any other facts?" asked Forrester, and received another shock when the doctor handed him a small piece of filmy white fabric.

"I found this beside the body," said the doctor. And added, as Forrester took it, "Note the peculiar odor."

Forrester lifted the fabric to his nose. Instantly he recognized the same pungent, drug-like smell which he had noticed the night he was attacked with the death mask. Examining the filmy bit of cloth, Forrester saw that it was a part of a lady's handkerchief which had been torn in half. In one corner the letter "S" was embroidered. Crumpling the handkerchief in his hand, Forrester pushed it into his waistcoat pocket.

"I believe I can make use of this," he said.