For several hours after his return to the little cabin Dan had ample leisure in which to think over his extraordinary interview. There could be no doubt that the conspirators, for such he had come to call them to himself, were determined and desperate enough to go to any lengths in accomplishing their designs. Whether his suspicions and activity in seeking Nancy had precipitated their plans, his unexpected capture seemed to embarrass his captors as much as it did himself. At least, he gathered this from Madame de la Fontaine's conversation. Whatever might be the motive of the lady's proposed confidence, poor Frost could see nothing for it but to await their disclosure and then seize whatever advantage they might open to him. Notwithstanding the fact that Dan had cautioned himself against trusting the flattery of his charming visitor, notwithstanding that he told himself to be forewarned, even by his own suspicions, was to be forearmed, he was in reality unconscious of the degree to which he had proved susceptible to the lady's blandishments, if indeed she had employed blandishments and had not merely given him the evidence of a good heart upon which his youth and naivetÉ had made a genuine impression.

Dan's experiences with girls up to this time had been limited. His emotional nature had never, as yet, been deeply stirred. But no one could be insensible to Madame de la Fontaine's beauty and charm, and her delightfully natural familiarity; and, finally, her fleeting kiss had seemed to Dan but evidence of a warm impulsive heart. To be sure, with all the good will in the world, he could not acquit her of being concerned in a mysterious plot—indeed, had she not admitted so much?—though, also, he must in justice remember that he knew very little of the nature of the plot in question.

As he paced restlessly back and forth the length of his prison, he tried to think clearly of the accumulating mystery. Was there a hidden treasure and how did the Marquis know about it? What part had the Southern Cross to play with its diabolical looking captain, and what could have become of Nancy? Then why had Madame de la Fontaine—but again his cheek would burn and remembrance of the bewitching Frenchwoman blotted out all else.

At half-past twelve Captain Bonhomme appeared again. This time he invited Dan to partake of luncheon with him on the condition once more of a parole. And Dan accepted. He and the Captain made their luncheon together, attended by the faithful Jean; and, though no mention was made to their anomalous position, the meal was not altogether a comfortable one. Captain Bonhomme asked a great many questions about the country, to which Frost was inclined to give but the briefest replies; nor, on his part, did he show more disposition to be communicative in response to Dan's questions about France. Jean regarded the situation with obviously surly disapproval. When the meal was finished, Frost was conducted back to his little cabin.

About two o'clock he saw the small boat put off for shore, and glancing in that direction, he was relieved to see Madame de la Fontaine already waiting upon the beach. Within half-an-hour he was again in her presence in the Captain's saloon, where their conversation had taken place in the morning.

The lady received him graciously. "Ah! monsieur Dan, I fear you have had a weary day of it; but it was impossible for me to return sooner."

"It is very kind of you to return at all," replied Dan, gallantly enough.

"Now, Monsieur, you are anxious, I know, that I keep my promise of the morning."

"Most anxious," said Dan.

"Without doubt. Come here, my friend, sit near me and listen attentively to a long story."

"You have consulted with the Marquis?"

"Mais oui. It was difficult, but I have brought him to my way of thinking. I am certain that it was an error in the first place not taking you into our confidence. Eh bien! Tell me, do you know how your foster-sister came to be in the charge of your mother at the Inn at the Red Oak?"

"Yes, I know what my mother has told me. The child was abandoned to her rather than left in her charge."

"Mais non" said Madame de la Fontaine; "General Pointelle was impelled to act as he did by the strongest motives,—nothing less than the tremendous task, undertaken for his country, to liberate the Emperor Napoleon from Elba. General Pointelle was a soldier,—more, he was a marÉchal of the Empire; the greatest responsibilities devolved upon him. It was impossible for him to be burdened with a child."

"But why, madame, did he not take my mother into his confidence?"

"Secrecy was imperative, monsieur. Even to this day, you do not know who General Pointelle actually was. His was a name well-known in France, glorious in the annals of the Empire; a name, too, familiar to you in a somewhat different connection. 'General Pointelle' was the nom-de-guerre, as it were, of FranÇois, Marquis de Boisdhyver, marÉchal de France."

"FranÇois! you say, FranÇois!" exclaimed Dan.

"Mais oui, monsieur; but that should hardly astonish you so much as the fact that he was a Boisdhyver. Why are you surprised?"

"Simply, madame," exclaimed Dan hastily, "by the fact that it is the same name as that of our Marquis."

"Not quite," corrected the lady; "our Marquis—as you say—is Marie-Anne-TimÉlon-Armand de Boisdhyver, the General's younger brother."

"Ah! and therefore Nancy's uncle?"

"Yes, the uncle of Nancy Frost, or of Eloise de Boisdhyver."

"I see," said Dan. "I begin to see."

"Eh bien, monsieur. General Pointelle—the marÉchal de Boisdhyver,—left the Inn at the Red Oak upon a mission for the Emperor, then at Elba. HÉlas! that mission ended with disaster after the Hundred Days; for, as you know, the Emperor was sent in exile to St. Helena; and, as you may not know, the MarÉchal de Boisdhyver was killed on the plains of Waterloo. Allons; when he left Deal, he concealed in a hidden chamber, which one enters, I believe, from a room you call the Oak Parlour, a large treasure, of jewels and gold. This treasure, saved from the debacle in France, he had brought with him to America, and he hid it in the Inn, for the future of his little daughter Eloise. You remember that your mother was to hear something of advantage to her and the child, did not the General return. It was the secret of the treasure and the directions to find it. Well, Monsieur, at Waterloo, you must know, the MarÉchal and his brother, the present Marquis, fought side by side. FranÇois de Boisdhyver fell, nobly fighting for the glory of France; Marie-Anne had the good fortune to preserve his life, but was taken prisoner by the English. Before the MarÉchal received his death wound, the two brothers spoke with each other for the last time. In that moment, monsieur, the Marquis FranÇois revealed to the Marquis Marie-Anne that he had abandoned his daughter in America and that he had concealed in your old inn a treasure sufficient to provide for her future. He charged his brother to go to America, if he survived the battle; claim the little Eloise; rescue the treasure, and return with her to France and restore the fallen fortunes of the House of Boisdhyver.

"It took the Marquis Marie-Anne a long time to carry out his brother's dying injunctions," said Dan.

"Ah! but yes. You do not realize that the Marquis Marie-Anne, after the fall of Napoleon, spent many years in a military prison in England, for I have already told you that he fell into the hands of the enemy on the field of Waterloo. When at last he was released, he was aged, broken, and in poverty. His brother, in those dreadful moments on the battlefield, had been able to give him but the briefest description of the Inn at the Red Oak and the hidden treasure. He did not tell him where the treasure was, but only how he might obtain the paper of instructions which the MarÉchal had concealed in a curiously-carved old cabinet in the Oak Parlour. The MarÉchal, monsieur, loved the mysterious, and chose the device of tearing into two parts this paper of directions and concealing them in different hiding-places of the cabinet. Those directions, after many years, grew vague in the younger brother's memory.

"Eh bien, the Marquis was at last able to make the journey to this country. You must remember he had nothing wherewith to prove his story, if he gave you his confidence at once; and so, he decided, to investigate quietly alone. But he won the confidence of Mademoiselle Nancy,—that is, of his niece, Eloise de Boisdhyver,—and revealed to her the secret of her identity and the mysterious story of the treasure. You follow me in all this, Monsieur Dan?"

"Perfectly, madame," Frost replied. "But as yet you have told me nothing of your own connection with this strange history."

"Pardon, dear boy," rejoined Madame de la Fontaine; "I was about to do so, but there is so much to tell. My own connection with the affair is quite simple. I am an old friend, one of the oldest, of Monsieur le Marquis de Boisdhyver, and, when I was a very young girl, I knew the MarÉchal himself. It has been my happiness to be able to prove my friendship for a noble and a fallen family. One day last summer, Monsieur de Boisdhyver told me his brother's dying words, and it was I, Monsieur Dan, who was able to give the money for this strange expedition. The poor Marquis had lost quite all his fortune."

"I understand," said Frost. "But, yet, madame, I do not see the necessity for the secrecy, the mystery, for these strange signals at night, for these midnight investigations, for this schooner and its rough crew, for Nancy's disappearance, for my own imprisonment here."

"Please, please," murmured Madame de la Fontaine, as she held up her hands in smiling protest. "You go too fast for me. Un moment, mon ami, un moment. It was sixteen years ago that the MarÉchal de Boisdhyver was a guest at the Inn at the Red Oak. You forget that the Marquis de Boisdhyver had no proof of his right to the treasure, save his own story, save his account of his brother's instructions on the field of Waterloo. By telling all he might have awakened deeper suspicions than by secrecy."

"That, I must say," Dan interrupted, "would hardly be possible."

"So!" exclaimed Madame de la Fontaine, with an accent of displeasure. "Ecoutez! Monsieur le Marquis was to come a month in advance, as he did come; take up his quarters at the Inn; reconnoitre the ground; and win, if possible, the confidence and aid of mademoiselle. He fortunately succeeded in this last, for he found it otherwise impossible to enter into the old wing of the Inn and examine the Oak Parlour. With the assistance of Eloise, this was accomplished at last, and the paper of directions was found; at least, found in part.

"Then I, having impressed the services of Captain Bonhomme and his ship the Southern Cross, set sail and arrived at the House on the Dunes only a few days ago, as you already know. The signals that you saw flashing at night were to indicate that all was well."

"The green light, I suppose," commented Dan, "was to indicate that; and the red—"

"Was the signal of danger. Because the Marquis discovered last night that you were not in the house; he flashed the warning that made Captain Bonhomme go to the House on the Dunes. Quite recently the manners of your friend, Mr.—eh—?"

"Pembroke?"

"Yes, Mr. Pembroke—led the Marquis to believe that he was being watched.

"I understand," said Dan, "but nothing you have told me so far, madame, accounts for Nancy's disappearance, and I am as anxious as ever to know where she is."

"Mademoiselle is perfectly safe, Monsieur Dan; I assure you. She left the Inn because she had fear of betraying our plans, particularly as she loved your friend, Mr. Pembroke."

"It is still strange to me, madame, that Nancy should distrust her oldest and best friends. But now you will let me see her?"

"Of course I shall soon, very soon, my dear boy. I have told you all, and now you will aid me to find the treasure that is your foster-sister's heritage, will you not?"

"Why certainly I want Nancy to have what is hers," replied Dan.

"Bravo, my friend. We are to count you one of us, I am sure."

"Just a moment," said Dan, resisting the temptation to touch the little hand that had been placed impulsively upon his arm. "May I ask one more question?"

"A thousand, my dear, if you desire."

"Why then, since until last night everything has gone as you planned it, why has not the treasure already been discovered?"

"Because, mon ami; the Marquis has only been able to visit the Oak Parlour at night. And also it was decided to wait until I arrived."

"With the schooner?" suggested Dan.

"With the schooner, if you will. And you may remember that it was only the day before yesterday that I reached your so hospitable countryside."

"Ah! I understand; so then all that you desire of me, madame, is that I shall permit the Marquis or anyone else whom you may select for the purpose, to make such investigation of the Oak Parlour as is desired."

"Yes, my friend; and also there is yet another thing that we desire."

"But suppose, madame, that I cannot agree to that?"

"Ah! cher ami, but you will. I confess—you must remember that the Marquis de Boisdhyver has been a soldier—that my friends have not agreed with me entirely. It has seemed to them simpler that we should keep you a prisoner on this ship, as we could so easily do, until our mission is accomplished. But,—I like you too much to agree to that."

Dan flushed a trifle, but he was not yet quite sure enough to fall in entirely with his charming gaoler's suggestions. "Madame de la Fontaine," he said after a moment's reflection, "I am greatly obliged to you for explaining the situation to me so fully. I shall be only too happy to help you, particularly in anything that is for the benefit of Nancy."

"I was sure of it. Now, my friend, there is a service that you can immediately render."

"And that is?" asked Dan.

"To entrust to me the other half of the paper of directions written by FranÇois de Boisdhyver, which you found in a secret cubby-hole in the old cabinet."

"What makes you think that I was successful in finding that, when the Marquis failed?"

"Because, at first having forgotten his precise directions after so many years, the Marquis could not find the fourth and last hiding-place in the cabinet, in which he knew the MarÉchal had placed the other half of the torn scrap of paper. Another time he did find the cubby-hole, and it was empty. So knowing he was watched by you and Mr. Pembroke, he decided that you must have found it. Is it not so, that you have it?"

"It is certainly not in my possession at this moment," said Dan.

"No, but you have it?"

"And if I have?"

"It is necessary for our success."

"Then, my first service, is to put you into complete possession of the secret?"

"If you will so express it."

"Very well, madame, I will do so; but, on one condition."

"And what is that, my friend?"

"That I be allowed to see Nancy, and that she herself shall ask me to do as you desire."

For a moment Madame de la Fontaine was silent. "Eh bien," she said at last, "you do not trust me?"

"But, dear madame, think of my situation, it is hard for me."

"Ah! I know it, believe me. C'est difficile. But I hoped you would trust me as I have you."

"Indeed, madame," exclaimed Dan, "I must try to think of everything, the mystery, this extraordinary mission upon which you are engaged, the fact that I am quite literally your prisoner. When I think about you, I know only you are beautiful, that you are lovely, and that I am happy near you."

She looked at him for a moment with a glance of anxious interrogation, as if to ask were it safe for her to believe these protestations. "You say, my friend," she asked at length, "that you care a little for me, for just me? C'est impossible. If Claire de la Fontaine could believe that, understand me, monsieur, it would be very sweet and very precious to her."

"I do care," cried Dan.

"Ah!" she exclaimed. "You have touched my heart. I am not a young girl, mon ami, but I confess that you have made me to know again the dreams of youth."

"Only let me prove that I care," cried Dan, considering but little now to what he committed himself.

"Let me prove," cried she, "that I too believe in you. I must first see the Marquis, and then, tonight, if it can be arranged, you shall receive from Eloise de Boisdhyver's own lips the request I have made of you. But if, for any reason, this cannot be arranged for to-night, you must be patient till morning; you must trust me to the extent of remaining on this ship. I cannot act entirely on my own judgment, but I assure you that in the end my judgment will prevail. And now, au revoir."

She placed her hand in his, and responded to the impulsive pressure with which he clasped it. Their eyes met; in Dan's the frankest expression of her conquest of his emotions; in her's a glance at once tender and sad, above all a glance that seemed to search his spirit for assurance that he was in earnest. Suddenly fired by her alluring beauty, Dan drew her to him and bent his head to hers.

"Ah! my friend," she murmured, "you are taking an unfair advantage of the fact that this morning I too rashly yielded to an impulse."

"I cannot help it," Dan stammered. "You bewitch me." He bent lower to kiss her cheek, when he suddenly thrilled to the realization that his lips had met hers.

A moment later Madame de la Fontaine was gone and Captain Bonhomme had reappeared in the doorway.