I confess that her attitude took me aback.

I was certainly unprepared for such a reception.

"I believed, madame, that you were in search of me?" I said, with polite apology.

"I certainly was not. I don't know you in the least," was her reply. "I went to the Tube to meet a friend who did not keep his appointment. Is it possible that you have been sent by him? In any case, it was very injudicious for you to approach me in that crowd. One never knows who might have been watching."

"I come as messenger from my friend, Sir Digby Kemsley," I said in a low voice.

"From him?" she gasped eagerly. "I—ah! I expected him. Is he prevented from coming? It was so very important, so highly essential, that we should meet," she added in frantic anxiety as we stood there in the darkness beneath the bare trees, through the branches of which the wind whistled weirdly.

"I have this letter," I said, drawing it from my pocket. "It is addressed 'For E. P. K.'"

"For me?" she cried with eagerness, as she took it in her gloved hand, and then leaving my side she hurried to a street lamp, where she tore it open and read the contents.

From where I stood I heard her utter an ejaculation of sudden terror. I saw how she crushed the paper in one hand while with the other she pressed her brow. Whatever the letter contained it was news which caused her the greatest apprehension and fear, for dashing back to me she asked:

"When did he give you this? How long ago?"

"On the night of January the sixth," was my reply. "The night when he left Harrington Gardens in mysterious circumstances."

"Mysterious circumstances!" she echoed. "What do you mean? Is he no longer there?"

"No, madame. He has left, and though I am, perhaps, his most intimate friend, I am unaware of his whereabouts. There were," I added, "reasons, I fear, for his disappearance."

"Who are you? Tell me, first."

"My name is Edward Royle," was my brief response.

"Ah! Mr. Royle," the woman cried, "he has spoken of you many times. You were his best friend, he said. I am glad, indeed, to meet you, but—but tell me why he has disappeared—what has occurred?"

"I thought you would probably know that my friend is wanted by the police," I replied gravely. "His description has been circulated everywhere."

"But why?" she gasped, staring at me. "Why are the police in search of him?"

For a few seconds I hesitated, disinclined to repeat the grave charge against him.

"Well," I said at last in a low, earnest voice, "the fact is the police have discovered that Sir Digby Kemsley died in South America some months ago."

"I don't follow you," she said.

"Then I will be more plain. The police, having had a report of the death of Sir Digby, believe our mutual friend to be an impostor!"

"An impostor! How utterly ridiculous. Why, I myself can prove his identity. The dead man must have been some adventurer who used his name."

"That is a point which I hope with your assistance to prove," I said. "The police at present regard our friend with distinct suspicion."

"And I suppose his worst enemy has made some serious allegation against him—that woman who hates him so. Ah! I see it all now. I see why he has written this to me—this confession which astounds me. Ah! Mr. Royle," she added, her gloved hands tightly clenched in her despair. "You do not know in what deadly peril Sir Digby now is. Yes, I see it plainly. There is a charge against him—a grave and terrible charge—which he is unable to refute, and yet he is perfectly innocent. Oh, what can I do? How can I act to save him?" and her voice became broken by emotion.

"First tell me the name of this woman who was such a deadly enemy of his. If you reveal this to me, I may be able to throw some light upon circumstances which are at the present moment a complete mystery."

"No, that is his secret," was her low, calm reply. "He made me swear never to reveal the woman's name."

"But his honour—nay, his liberty—is now at stake," I urged.

"That does not exonerate me from breaking my word of honour, Mr. Royle."

"Then he probably entertains affection for the woman, and is hence loth to do anything which might cause her pain. Strangely enough, men often love women whom they know are their bitterest enemies."

"Quite so. But the present case is full of strange and romantic facts—facts, which if written down, would never be believed. I know many of them myself, and can vouch for them."

"Well, is this unnamed woman a very vengeful person?" I asked, remembering the victim who had been found dead at Harrington Gardens.

"Probably so. All women, when they hate a man, are vengeful."

"Why did she hate him so?"

"Because she believed a story told of him—an entirely false story—of how he had treated the man she loved. I taxed him with it, and he denied it, and brought me conclusive proof that the allegation was a pure invention."

"Is she young or middle-aged?"

"Young, and distinctly pretty," was her reply.

Was it possible that this woman was speaking of that girl whom I had seen lying dead in my friend's flat? Had he killed her because he feared what she might reveal? How dearly I wished that I had with me at that moment a copy of the police photographs of the unidentified body.

But even then she would probably declare it not to be the same person, so deeply had Sir Digby impressed upon her the necessity of regarding the affair as strictly secret.

Indeed, as I walked slowly at her side, I saw that, whatever the note contained, it certainly had the effect upon her of preserving her silence.

In that case, could the crime have been premeditated by my friend? Had he written her that secret message well knowing that he intended to kill the mysterious woman who was his deadliest enemy.

That theory flashed across my brain as I walked with her, and I believed it to be the correct one. I accepted it the more readily because it removed from my mind those dark suspicions concerning Phrida, and, also, in face of facts which this unknown lady had dropped, it seemed to be entirely feasible.

Either the unsuspecting woman fell by the hand of Digby Kemsley or—how can I pen the words—by the hand of Phrida, the woman I loved. There was the evidence that a knife with a triangular blade had been used, and such a knife had been, and was still, in the possession of my well-beloved; but from what I had learned that night it seemed that, little as I had dreamed the truth, my friend Digby had been held in bondage by a woman, whose tongue he feared.

Ah! How very many men in London are the slaves of women whom they fear. All of us are human, and the woman with evil heart is, alas! only too ready to seize the opportunity of the frailty of the opposite sex, and whatever may be the secret she learns, of business or of private life, she will most certainly turn it to her advantage.

It was similar circumstances I feared in the case of dear old Digby.

I was wondering, as I walked, whether I should reveal to my companion—whose name she had told me was Mrs. Petre—the whole of the tragic circumstances.

"Is it long ago since you last saw Digby?" I asked her presently, as we strolled slowly together, and after I had given her my address, and we had laughed together over my effective disguise.

"Nearly two months," she replied. "I've been in Egypt since the beginning of November—at Assuan."

"I was there two seasons ago," I said. "How delightful it is in Upper Egypt—and what a climate in winter! Why, it is said that it has never rained there for thirty years!"

"I had a most awfully jolly time at the Cataract. It was full of smart people, for only the suburbs, the demi-monde, and Germans go to the Riviera nowadays. It's so terribly played out, and the Carnival gaiety is so childish and artificial."

"It amuses the Cookites," I laughed; "and it puts money in the pockets of the hotel-keepers of Nice and the neighbourhood."

"Monte is no longer chic," she declared. "German women in blouses predominate; and the really smart world has forsaken the Rooms for Cairo, Heliopolis, and Assuan. They are too far off and too expensive for the bearer of Cook's coupons."

I laughed. She spoke with the nonchalant air of the smart woman of the world, evidently much travelled and cosmopolitan.

But I again turned the conversation to our mutual friend, and strove with all the diplomatic powers I possessed to induce her to reveal the name or give me a description of the woman whom she had alleged to be his enemy—the woman who was under a delusion that he had wronged her lover. To all my questions, however, she remained dumb. That letter which I had placed in her hand had, no doubt, put a seal of silence upon her lips.

At one moment she assumed a haughtiness of demeanour which suited her manner and bearing, at the next she became sympathetic and eager. She was, I gauged, a woman of strangely complex character. Yet whom could she be? I knew most, perhaps even all, of Digby's friends, I believed. He often used to give cosy little tea parties, to which women—many of them well known in society—came. Towards them he always assumed quite a paternal attitude, for he was nothing if not a ladies' man.

She seemed very anxious to know in what circumstances he had handed me the note, and what instructions he had given me. To her questions I replied quite frankly. Indeed, I repeated his words.

"Ah! yes," she cried. "He urged you not to misjudge me. Then you will not, Mr. Royle—will you?" she asked me with sudden earnestness.

"I have no reason to misjudge you, Mrs. Petre," I said, quietly. "Why should I?"

"Ah! but you may. Indeed, you most certainly will."

"When?" I asked, in some surprise.

"When—when you know the bitter truth."

"The truth of what?" I gasped, my thoughts reverting to the tragedy in Harrington Gardens. Though I had not referred to it I felt that she must be aware of what had occurred, and of the real reason of Digby's flight.

"The truth which you must know ere long," she answered hoarsely as we halted again beneath the leafless trees. "And when you learn it you will most certainly condemn me. But believe me, Mr. Royle, I am like your friend, Sir Digby, more sinned against than sinning."

"You speak in enigmas," I said.

"Because I cannot—I dare not tell you what I know. I dare not reveal the terrible and astounding secret entrusted to me. You will know it all soon enough. But—there," she added in a voice broken in despair, "what can matter now that Digby has shown the white feather—and fled."

"He was not a coward, Mrs. Petre," I remarked very calmly.

"No. He was a brave and honest man until——" and she paused, her low voice fading to a whisper that I did not catch.

"Until what?" I asked. "Did something happen?"

"Yes, it did," she replied in a hard, dry tone. "Something happened which changed his life."

"Then he is not the impostor the police believe?" I demanded.

"Certainly not," was her prompt reply. "Why he has thought fit to disappear fills me with anger. And yet—yet from this letter he has sent to me I can now see the reason. He was, no doubt, compelled to fly, poor fellow. His enemy forced him to do so."

"The woman—eh?"

"Yes, the woman," she admitted, bitter hatred in her voice.

Then, after a pause, I said: "If I can be of any service to you, Mrs. Petre, for we are both friends of Digby's, I trust you will not fail to command me."

And I handed her a card from my case, which I had carried expressly.

"You are very kind, Mr. Royle," she replied. "Perhaps I may be very glad of your services one day. Who knows? I live at Park Mansions."

"And may I call?"

"For the present, no. I let my flat while I went abroad, and it is still occupied for several weeks. I shall not be there before the first week in March."

"But I want to find Digby—I want to see him most urgently," I said.

"And so do I!"

"How can we trace him?" I asked.

"Ah! I am afraid he is far too elusive. If he wishes to hide himself we need not hope to find him until he allows us to," she replied. "No, all we can do is to remain patient and hopeful."

Again a silence fell between us. I felt instinctively that she wished to confide in me, but dare not do so.

Therefore I exclaimed suddenly:

"Will you not tell me, Mrs. Petre, the identity of this great enemy of our friend—this woman? Upon information which you yourself may give, Digby's future entirely depends," I added earnestly.

"His future!" she echoed. "What do you mean?"

"I mean only that I am trying to clear his good name of the stigma now resting upon it."

The handsome woman bit her lip.

"No," she replied with a great effort. "I'm sorry—deeply sorry—but I am now in a most embarrassing position. I have made a vow to him, and that vow I cannot break without first obtaining his permission. I am upon my honour."

I was silent. What could I say?

This woman certainly knew something—something which, if revealed, would place me in possession of the truth of what had actually occurred at Harrington Gardens on that fatal night. If she spoke she might clear Phrida of all suspicion.

Suddenly, after a pause, I made up my mind to try and clear up one point—that serious, crucial point which had for days so obsessed me.

"Mrs. Petre," I said, "I wonder if you will answer me a single question, one which does not really affect the situation much. Indeed, as we are, I hope, friends, I ask it more out of curiosity than anything else."

"Well, what is it?" she asked, regarding me strangely.

"I want to know whether, being a friend of Digby's, you have ever met or ever heard of a certain young lady living in Kensington named Phrida Shand."

The effect of my words was almost electrical. She sprung towards me, with fire in her big, dark eyes.

"Phrida Shand!" she cried wildly, her white-gloved hands again clenched. "Phrida Shand! You know that woman, eh? You know her, Mr. Royle. Is she a friend of yours?—or—or is she your enemy? Your friend, perhaps, because she is pretty. Oh, yes!" she laughed, hysterically. "Oh, yes! Of course, she is your friend. If she is—then curse her, Mr. Royle—invoke all the curses of hell upon her, as she so richly deserves!"

And from her lips came a peal of laughter that was little short of demoniacal, while I stood glaring at her in blank dismay.

What did she mean? Aye, what, indeed?