Mr. Rookley swung his heavy body to and fro on his heels and toes, and pursed up his official mouth.

“Mr. Robinson,” he said, “I must warn you that you are playing an exceedingly dangerous game.”

“May I suggest,” Westerham remarked, more bluntly than before, “that you are doing precisely the same?”

“What do you mean, sir?”

“I mean that you are not keeping strictly to your duty. You seem to be taking upon yourself a great many things which it is not your business to do—certainly you are assuming a great many prerogatives that you have no right to.”

“What do you mean, sir?” reiterated the detective.

“Tut, tut, my dear sir,” said Westerham, “sit down and try to compose yourself, while I endeavour to explain the precise situation.

“First,” Westerham continued, emphasising the “first” by touching his left forefinger with his right, “although I am not very much acquainted, thank goodness, with criminal procedure in this country, I am at least aware of this—that the law of England regards every man as innocent until he has been proved guilty. But you, under some misapprehension of your duties, appear to assume that I am guilty until I have proved myself innocent.

“Now, of what am I guilty? Nothing except of absenting myself from my rooms, which it is my innocent privilege and pleasure to do. You inquire of my antecedents. What do they matter to you? They are my business alone.

“However,” he went on, eyeing the now disconcerted Mr. Rookley, “in order that you may not be too harsh in your judgments I will enlighten your ignorance to a certain extent. I came here on the introduction of Lord Dunton, who is a most intimate friend. I paid six months' rent in advance. I furnished these rooms at no small expense, and I purchased one of the best motor cars on the market.

“Now I wish particularly to draw your attention to the fact that I did not offer to pay for any of these things by cheque. I paid for them all out of hand by bank-note. In fact, you will see for yourself that since I took up my abode here I must have spent perhaps a couple of thousand pounds; all of which I have paid out in hard cash.

“Were these bank-notes stolen? Certainly not. Had they been, the fact must inevitably have been discovered. No, strange as it may seem to you, I came by those notes quite honestly.

“It is not your business to do so, but if you care to take the trouble you are at perfect liberty to trace them. However, to save you unnecessary labour, I may as well tell you that those notes were paid over to me by Lord Dunton, in return for a cheque which I gave him. Why I chose to conduct my business on those lines is my own affair.

“More than this I have no intention of revealing. You are, of course, at perfect liberty to make every inquiry you please of Lord Dunton, but I fancy you will obtain very small satisfaction from him.”

“Of course,” said Mr. Rookley, desirous of putting on an appearance which would suggest that he was not entirely baffled—“of course Lord Dunton may refuse to give any information, for the simple reason that such an explanation may be inconvenient to himself.”

“I do not quite follow you,” remarked Westerham.

“What I intended to imply,” said Mr. Rookley, “is that your friendship may not be so welcome to Lord Dunton as Lord Dunton's friendship is to you.”

“I think you are very insolent, Mr. Rookley,” said Westerham.

“Possibly,” answered the man from Scotland Yard; “but I think I have some justification for being rude. Now, although it is true that I cannot ascertain where you slept last night, I am at any rate acquainted with some of your movements.”

Westerham started. This was growing a little more awkward than he had bargained for. It even occurred to him that it might be foolish to withhold too much information from Mr. Rookley. But, on the other hand, if he revealed his identity his troubles would be greatly increased, for it would inevitably lead to a break with Melun and that would double his difficulties in probing the mystery of the Premier's secret.

“Yes,” Mr. Rookley went on, with a return to his old superiority and ease of manner; “you attended the Premier's reception last night”—he paused that his words might have more dramatic force—“and you went under the auspices of Captain Melun.”

“Indeed,” said Westerham, “you seem to be remarkably well informed.”

“I am,” agreed Mr. Rookley, shutting his mouth with a snap.

“I am,” he continued, “and I know this—that either you must be a very foolish, a very ignorant, or a very bad young man to have had the audacity to attend Lord Penshurst's reception under such a guardianship.”

“It is really very kind of you to make such distinctions,” laughed Westerham. “Only, as it happens, there is another alternative which you have not suggested. It is not my business to point it out to you, but I will give you the opportunity of discovering it for yourself. I know quite enough of Captain Melun to prevent my pleading ignorance or folly in the cultivation of his acquaintance; on the other hand, if you suggest that I am apparently enjoying his friendship because my ideas of life are the same as his, then you are wrong again. Can you think of any other reason for my being with Captain Melun?”

“None,” said the detective, with what was meant to be a most significant air.

“Then,” said Westerham, “suppose we adjourn this conversation sine die. It affords me very little pleasure, and apparently gives you uncommonly little satisfaction. Before you go, however, I am afraid I must add to your troubles. I assure you that I have not the faintest notion who broke into my rooms and who gagged my valet, any more than I have the remotest idea what the motive could possibly be. There were a good many things, scarf-pins and the like, lying about all over the place, but nothing has been stolen.”

“Oh,” said the detective with deep meaning, “but suppose they were looking for something else quite other than articles of value—I should say of intrinsic value. Suppose that someone had a notion that he would like to recover something you had no right to be possessed of; or suppose that the person who broke in imagined that he might find something among your papers which would be of use to him?”

“Now, my dear sir,” said Westerham, “I do not wish to insult you, but really you are a very poor judge of human character. Do you suppose I should not know if whatever I had no right to be possessed of had gone? Do you think that if some paper or papers which might give someone else a hold over me had been taken I should not also by this time be acquainted with the fact? And in either of those cases, should I be so entirely indifferent to the matter as I am now? No, I assure you I think that there has been some mistake.”

“Now look here, Mr. Robinson,” said the detective, with a more friendly air, “let me ask a straight question. Do you suspect that Captain Melun has had a hand in this?”

“No,” replied Westerham, with emphasis, “I do not. I feel certain that he has had nothing to do with it.”

“Is there no one else, then, whom you can possibly conceive guilty of such an outrage?”

Westerham gave himself up to a few minutes of genuine hard thinking.

“No,” he said at last slowly; “I can think of no one in the world who would have any object in treating my rooms in this way.”

“Then surely,” cried the detective, “if it is a mystery to you, you would like the matter cleared up?”

“Quite so,” said Westerham, with a smile, “cleared up with the assistance of Mr. Rookley. No, thank you very much for your kind offer, but I will clear the matter up for myself. In the meantime, as I see no reason why you should detain me, I will not detain you. Allow me to wish you good-day.”

Without another word he walked into his bedroom and shut the door sharply.

When Westerham told Rookley that he had no conception of the identity of his mysterious visitor he spoke the truth; nor, cudgel his brains as he might, could he advance any theory which satisfied him. It seemed that the best thing he could do was to send for Melun. The captain, he reflected, was more acquainted with this sort of dealing than he was, and might possibly throw some light on the matter. So for Melun he sent.

The captain came with a bad grace at about eight o'clock. He had already seen in the evening papers various accounts of the ransacking of Westerham's rooms.

Westerham began by detailing to him the conversation with the detective, to every word of which the captain listened with a great attention, here and there putting in a question which quite convinced Sir Paul that Melun knew nothing of the affair.

However, he was determined to see what Melun would say if he asked him point blank whether he had been playing the burglar.

Upon the question being put to him, Melun laughed quite easily and shrugged his shoulders.

“My dear fellow,” he said, “once bitten, twice shy. My attempt to burgle you on the Gigantic was not so successful as to tempt me to repeat the performance. Besides, I am a fairly good judge of my fellow-men, and I have given up all hope of discovering anything in your past or your present which would lead me to the delectable state of being able to dictate to you.”

“Thank you,” said Westerham, “that is at least frank.”

“I am learning,” returned Melun, “that it is scarcely worth while to be anything else with you.”

“Thank you again,” said Westerham. “And now suppose I ask you whether you can throw any light on the subject?”

“Now,” said Melun, “you are asking a really sensible question. I can. What is more, I think I can completely clear up the mystery for you.”

“So you did have a hand in it, after all?” cried Westerham.

“Well, yes, I had a hand in it; but I took no part in the actual burgling.”

Sir Paul stared at him in amazement. “What do you mean?” he demanded.

“First of all,” said Melun, “what was the description of the mysterious stranger given by your valet?”

“Very tall, very thin, with reddish hair and reddish moustache, and, so far as he could see through the mask on his face, grey eyes. His hands, as Blyth had good reason to notice, were very large and sunburnt, with uncommonly well-kept nails.”

Melun nodded his head. “Good,” he said, “the description tallies exactly with the gentleman I suspected of having been here this afternoon.

“You may have noticed,” he continued, “that one of the men most in evidence at Downing Street last night was the Premier's private secretary, the Hon. Claude Hilden.”

“Yes,” said Westerham, eagerly, “what of him?”

“He burgled your rooms,” said Melun, calmly.

“What!” Westerham jumped out of his chair and stood over Melun. “What do you mean? Why, it is impossible. If he did that it must have been by Lord Penshurst's orders, and what, in the name of Heaven, could they have expected to find here?”

“Exactly what Hilden came to find—what he did find, and what he took away with him.”

“In the name of Heaven, what?” asked Westerham, to whom things were becoming a little too complicated for him to follow.

“What Hilden found,” said Melun, slowly and precisely, “were Lady Kathleen's diamonds.”

“Lady Kathleen's diamonds!”

“Yes,” answered Melun, smiling as though with intense relish of an infinitely fine jest, “Lady Kathleen's diamonds.

“They were missed shortly after your departure, and you were at once suspected of being the author of the theft. And therefore Lord Penshurst, knowing that Bagley had made one attempt before, and that I was connected with Bagley, at first suspected me.

“In fact, at about two in the morning, Hilden came around to my rooms with the Premier. They roused me from sleep and taxed me with the theft, Lord Penshurst threatening that if I did not give them up he would certainly not accede to the other terms which I am asking of him.

“I told him quite frankly that I did not take them but that I strongly suspected you.”

“You scoundrel!” cried Westerham.

In his sudden rage he would have seized Melun by the throat; but Melun, whom Westerham had never seen more calm and self-possessed, pushed his hand aside and said, “Softly, softly! you had better hear me out.”

“Go on!”

“I told them,” continued Melun, “that it would be folly to rouse you as they had aroused me. In fact, I told them that you were a strong man armed—that any attack made on you or your rooms in the small hours would inevitably lead to one of them being damaged, which would only result in awkward police-court proceedings and painful revelations.”

“You scoundrel! You scoundrel!” cried Westerham again.

“Wait a minute, my dear fellow; hear me out,” pleaded Melun. “You may consider that you have played the game with me, but that is not my own view of things. It was necessary to teach you a lesson. In your nice, strong, masterful way you were under the impression that you had to deal with a pack of cowards and curs.”

“So I have,” said Westerham, grimly.

“Perhaps; but one of them is not quite so impotent as you judged him, and if you reflect a moment you will see, at any rate, that you are at present in a rather awkward predicament. However, to get on with my tale.

“I had you watched this morning, and as soon as you left your rooms I slipped in here with the diamonds.”

“But you said you had not taken them,” said Westerham.

“So I did, but I took them none the less. I got rid of your man for a minute on some pretext, and just jammed them into the pocket of the coat you had worn the night before. Then I at once communicated with Downing Street. I could not tell them where the diamonds actually were, for that would have given me away, but I knew that Lord Penshurst and Hilden were sufficiently desperate to turn your place upside down to find them. They did find them, for Hilden telephoned the fact to me half an hour before you sent for me.”

“Good Lord!” said Westerham, and held up his hand for silence. He wished to think. Matters were becoming more and more difficult to understand. Lord Penshurst went in dread of Melun—so great a dread that he even had to confide in his nephew and his private secretary when Melun pressed him too hard. It was evident, too, that Melun's grip of the Premier must be of the most remorseless kind, or such a man as Lord Penshurst would never stoop to countenance such deeds on Melun's part.

This was bad enough, but the whole affair assumed a far more sinister aspect when Westerham reflected that Lady Kathleen must of necessity be acquainted with Lord Penshurst's expedition in the small hours, and of her cousin's burglarious exploits in the afternoon.

“No wonder,” groaned Westerham to himself, “she did not trust me. No wonder! No wonder! Oh, the shame of it! This is the hardest part of all—to be suspected, and to be suspected of such a mean and dastardly thing as this.”

“Good Heavens!” he cried aloud, “but for the fact that I should be hung for it, which would unfortunately spoil my chances in certain directions, I think I could shoot you on the spot.”

“Just so,” said Melun, “but I feel safe in the knowledge that you won't.”

“I'll tell you what I will do,” said Westerham, “and I have every justification for doing it—I will go back on my agreement with you here and now. In half an hour I will be in Downing Street and expose the whole thing. Yes, by Heavens! And if Lord Penshurst won't move in the matter himself, then I will see to it that you are prosecuted.”

“No, you won't,” said Melun. “The question really involved is a matter of many men's lives, and one man's life, even yours, will not stand in the way of this secret being kept.”

“Lord Penshurst is no murderer, even though you may be,” cried Westerham, indignantly.

“Perhaps not, my dear sir, perhaps not; but, at the same time, the situation is such that he cannot possible prosecute.”

“What do you mean?” thundered Westerham, again laying his hand roughly on Melun's shoulder.

“Pardon me,” Melun answered, shaking himself free, “but that is my business—and Lord Penshurst's business.”

Poor little Lady Kathleen sobbed till she could sob no more. Then she lifted her head wearily, mopped her swollen eyes, and, gathering herself together, walked slowly back to the Hall.

She went at once to her father's room, to find the Premier in a scarcely less pitiable frame of mind than she was in herself.

The old man was sitting at his desk, his head buried in his hands, though the table was littered with papers requiring urgent attention.

Kathleen walked up behind him, and, placing one of her hands on his head, stroked his hair gently.

“Poor father!” she said.

“Heaven help us, my dear!” said Lord Penshurst, and he stood up and took his daughter in his arms, holding her almost as though he were afraid she might be taken from him.

After a little while he became calmer, and began to speak of the dreadful thing which weighed so upon both their spirits.

But even while he spoke of it he looked cautiously about, as though he were fearful that other ears might be listening.

“So you see, little girl,” he said, “that your very kindly estimate of the red-headed man Robinson was entirely wrong. He didn't look like a scoundrel, but he is one. He is not even a scoundrel of Melun's description. Upon my soul, I think I prefer the blackmailer to the mere thief.”

“Do you think,” asked Kathleen, searching her father's face, “that, after all, this is not some of Melun's work?”

“Why should it be?” returned her father.

“I don't know, I am sure,” said Kathleen, doubtfully, “except that I have a sort of feeling that it is.”

“Why?” asked her father.

Then, for the first time, Lady Kathleen told him of her meeting with Bagley in Hyde Park.

“Oh, my dear! my dear!” cried her father, taking her in his arms again. “How many more sacrifices are you prepared to make for me? If I had not confided in you I do not know what I should have done. I assure you that it is only because I dread the awful consequences that would come if my secret were discovered that has prevented me from taking my life. But, as you know, the shedding of my blood would mean the shedding of blood all over the world. Sometimes I think the dread of it is driving me out of my mind.

“And there does not seem to be any hope of getting the thing back—no hope of it at all. By George! I wish we were back in the good old days. Then I could put that Melun on the rack. I'd get the secret out of him somehow.

“But he is too slippery. I even made arrangements to have him watched, but he beats our men all the time. He is here to-day and gone to-morrow. He appears and he vanishes—Heaven only knows how.

“And now, to add to our perplexities, we have got this red-haired giant, who seems to be even more unscrupulous than Melun. Certainly he is more bold. To my way of thinking, it was only a bold stroke to win your confidence that he dealt with Bagley as he did.”

“Oh, father!” cried Kathleen, “I cannot believe that.”

“Nonsense, my dear. Do you suppose that a man who is hand in glove with Melun comes across you and Bagley in the Park by accident? Why, it is one chance against a hundred million.”

“But still it is a chance,” urged Kathleen.

“My dear little girl,” said the Premier, gently, while he patted her cheek, “I am afraid that you are of a very trusting disposition, though that has certainly been to the advantage of your poor old father.

“No, no!” he went on. “Depend on it, he was there by arrangement.

“Besides, how otherwise should he know who you were? And you say he suggested that he should drive you back to Downing Street?

“Gad! it almost makes one admire the man to think of his cool cheek. To drive you back to Downing Street indeed!”

“And yet, father, in spite of it all, I really believe the man's honest. You see, you cut me short. I have something else to tell you yet.”

Lord Penshurst eyed Kathleen uneasily.

“What is it now?” he asked, with a sad little laugh.

“Why,” said Lady Kathleen, and for a moment she felt unaccountably nervous and shy, “he was here this afternoon.”

“What!” roared the Premier; “he was here this afternoon? Why did you not tell me? I would have had the fellow flogged out of the place.”

“Gently, father, gently,” urged Lady Kathleen, “aren't you speaking rather loud?”

“I suppose I am,” said Lord Penshurst, bitterly. “But tell me about it.”

In a very few words Lady Kathleen outlined her interview with Westerham in the Deer Park.

“You know, father,” she concluded, “I almost believe he was speaking the truth when he said that he was quite different from the man we believed him to be.”

“Rubbish, my dear,” snapped the Premier, “he is only a gentlemanly scoundrel—that is all.

“I wonder how long we shall be able to keep Hilden in ignorance of what is really the matter,” he continued. “The dear chap has behaved splendidly—did everything I asked him without a murmur, even to the extent of burglary this afternoon. By the way, he has got your diamonds back. He has just 'phoned me from Downing Street.”

“Oh, let them go! Let them go!” cried Lady Kathleen, with intense weariness. “Their presence seems only to make matters worse.”

Suddenly she threw herself into her father's arms.

“Oh, father, father!” she cried. “Let us do everything we can. Don't let us give up hope. We have still got a fortnight left in which to get that dreadful secret back. Don't let us give up hope. I would rather disguise myself and go out and search for it than have to endure what it means if we fail.”

“Don't cry, my dear. Don't cry. Believe me, I am doing everything I possibly can without giving anything away. But already it seems to me—perhaps I only imagine things—that the servants and people suspect that something is wrong.

“That is why we have got to be brave and look cheerful. I know it will be dreadful for you to have to look after the house party—and the people come to-morrow. Still, it cannot be helped. We have got to go through with it, but after the dance we will go back at once, and then I assure you that if it costs me my life I will make that Melun disgorge.”

Kathleen smiled at her father through her tears.

“You dear old fire-eater,” she said. “I really believe you would.”

“My daughter,” the Premier said, “there has never been a murderer in this family to my knowledge; but I swear to you that if I have to settle the scoundrel myself you shall not marry Melun. Heavens! The price of silence is too big altogether.”