"It's no good going in now," said Gatton, in a weary voice; "in fact it might be dangerous. We have to consider the possibility of fire, however," he added.

Voices of sleepers awakened and cries of inquiry sounded now from all over the inn; for naturally the household had been aroused by the tremendous noise of the explosion. For my own part I was altogether too dazed to conjecture what had happened. But that Gatton had saved me from some deadly peril I was well convinced. Stirrings and the noise of footsteps came from an adjoining room, and presently in his night attire Martin appeared, very bemused.

"Mr. Addison," he began, and stared from me to my companion.

"Let no one leave their rooms," said Gatton decisively, "until I give them permission."

"Eh," began Martin heavily.

"I am a police officer," added Gatton; "and you will all do as I direct. Does any one sleep on the same floor as Mr. Addison?"

"No, sir," replied Martin, who was not yet more than half awake, but who nevertheless had been impressed by the Inspector's authoritative manner.

Sounds of footsteps from the floor above now became audible, whereupon:

"Order every one to remain in their rooms!" repeated Gatton.

Martin, raising his voice, obeyed him.

"What are your arrangements in the case of fire?" continued the Inspector.

Several betousled heads were peeping down from the landing above but no one spoke until Martin collected his ideas sufficiently to reply:

"There's buckets in the stables—and there's the well. Wilkins sleeps over the stables—"

"Can you make him hear without going downstairs?"

"I can try," was the answer.

Martin walked to a window which lighted the landing, and threw it widely open. Leaning out:

"Wilkins!" he roared—"Wilkins!"

"Aye, aye, boss!" came faintly from somewhere below.

"Tell him to stand by with fire-buckets, but not to leave the yard without orders from me," directed Gatton.

Martin issued these instructions in a voice which must have been audible at Leeways, and then stood scratching his head stupidly.

But indeed of all the bewildered company who gathered that night beneath the roof of the Abbey Inn, I think I was the most nonplused of all, and turning to Gatton:

"For God's sake tell me what it all means!" I said.

"It means," he answered, and even through his disguise I recognized the old grim smile, "that only a match stood between you and eternity! Even now, we cannot afford to sit down, but I am not anxious to pass your door for a few minutes. As we both have much to say, let us find a room where we can talk."

Accordingly we went up to a large empty room at the back of the inn. Through the open doorway I could hear the excited voices of the entire staff of the establishment, who had congregated in Martin's room across the landing. Never in the history of the Abbey Inn had such doings taken place.

"Perhaps," continued Gatton, "it will save time if you tell me exactly what you have done first."

"Very well," I said; "but before I begin—when did you arrive?"

"An hour and a half after receiving your code telegram! I came by car. The car is at Manton now."

"Why this disguise?"

"I will explain in a moment. But meanwhile—your own story."

At that, although consumed with impatience, I quickly outlined my movements from the time of my arrival at Upper Crossleys, the Inspector following me closely. The tale concluded:

"Now, Gatton!" I cried—"for heaven's sake tell me what it all means!"

"I will tell you all I know," he replied slowly, "In the first place I had two reasons for suggesting the visit to Friar's Park. I had formed an opinion that the 'cat-woman' was interested in you. Whether because she regarded you as dangerous or from some other cause I could not determine. And I thought of a plan for finding out if she was by any chance associated with Friar's Park. It was to send you down here (a) to make straightforward inquiries, and (b) to 'draw the cat'!"

"Very good of you!" I murmured.

"I warned you it was dangerous!" said Gatton grimly. "But I am pleased to say the plan worked to perfection. Your own inquiries have been highly satisfactory and you have also 'drawn the cat'! Now just to show you how dramatic your discoveries really were I will explain my second and more important reason and the one which primarily had prompted me to turn my attention to Friar's Park. A few hours before you came to the Yard the other morning—to see the bag dropped in the water by Eric Coverly—I had been in touch with the solicitors who had acted for the late Sir Burnham."

"Ah!" I exclaimed—"what had they to say?"

"I was seeking information of course respecting the entail; in short, trying to fathom the mystery of what Eric Coverly would have had to gain by getting his cousin out of the way. I learned that financially he gained nothing but a bundle of debts. Friar's Park was mortgaged to the hilt. Furthermore, Lady Burnham Coverly had a life interest in the property under the will of her husband.

"Next, from the senior partner, a solicitor of the old school who still retained pleasant memories of Sir Burnham's port, I learned a number of very significant details."

He paused, staring at me oddly; and the familiar expression beneath the unfamiliar disguise was very curious. Then:

"About seven or eight years ago," he resumed, "shortly after his return from Egypt, according to Mr. Hardacre, the solicitor, something occurred which made a changed man of his client, Sir Burnham. You will note, Mr. Addison, shortly after his return from Egypt. He realized upon quantities of securities, and raised a big sum of ready money, which he disposed of in some way which has always remained a mystery to Mr. Hardacre. In short, within a period of three years or less, from being a wealthy man, he became a poor one.

"Next, he sent Mr. Roger Coverly, his only child, then a mere lad, abroad in care of a tutor; Mr. Hardacre never knew for what reason as there was apparently nothing wrong with the boy's health! He began to dismiss his servants. The greater part of Friar's Park was shut up and allowed to fall into decay. Finally, to Mr. Hardacre's surprise and grief, Sir Burnham mortgaged the property. But it was the terms of the mortgage—which I was privileged to inspect—which aroused my curiosity.

"In brief, the mortgagee agreed, in the event of Sir Burnham's death, to allow the widow to retain possession of the property for life, whether payments fell in arrears or otherwise!"

"But this—" I exclaimed.

"Is, as a friend of yours once remarked, as mad as 'Alice in Wonderland'! I agree. But to continue. At the time that this extraordinary agreement was drawn up, Mr. Hardacre went down to Friar's Park, of course; and he was a witness of several most singular and significant occurrences. For instance, on the evening of his arrival, whilst he was dressing for dinner, Sir Burnham came running to his room and begged of him to lock his door and to remain in his room until his host gave him permission to come out! He was particularly warned against admitting any one who might knock in the interval!"

"Good heavens!" I cried—"and did any one knock?"

"No one; but about half an hour later Sir Burnham came and released him. Mr. Hardacre was unspeakably distressed to observe that Sir Burnham looked white and ill; in fact, in Mr. Hardacre's own words, five years older! Again, quite by accident, on the same night, he came upon his host kneeling in the chapel—in those days it still boasted a roof—deep in prayer. An atmosphere of indescribable horror, he declared, had settled upon Friar's Park, and although, as he confessed, he had no evidence to prove the correctness of his theory, he nevertheless traced this to the person of the mortgagee. For it seemed to correspond roughly with the appearance in the neighborhood of this man—whom he now met for the first time."

Again Gatton paused, taking out his pipe and pouch, and:

"Who was this person?" I asked.

"A certain Dr. Damar Greefe!"

"Good God!" I cried—"where is all this leading us, Gatton?"

"It is leading us slowly to the truth, Mr. Addison, and that truth, when we come to it, is going to be more horrible than we even suspect. Passing over much of Mr. Hardacre's evidence, I come to the death, in Switzerland, of Mr. Roger Coverly, under circumstances so obscure that I fear we shall never know the particulars. Of one thing, however, I am assured: there was foul play."

"You mean that Roger Coverly was—murdered?"

"I really don't doubt it," replied Gatton, who, having filled his pipe, now lighted it. "I believe he was the first victim."

"The first victim?"

"Mr. Addison, I agree with the late Sir Burnham's solicitor, that the spider at the heart of this web is Dr. Damar Greefe. The shock of his son's premature death led to a collapse from which Sir Burnham never recovered, and Friar's Park entered upon the final phase during which it was occupied by Lady Burnham who seems to have been wholly under the influence of this Eurasian doctor."

"But, my dear Gatton!" I cried—"where is Lady Burnham?"

"In my opinion, dead!" he answered solemnly. "Oh, it sounds preposterous, but in the case of this lonely woman who had apparently no living relatives and who was estranged from Sir Marcus and the other members of her husband's family, it was no very difficult matter to hush up the fact of her death."

"But, Gatton, you don't mean that she, too, met with foul play?"

"Most certainly I don't! It is as clear as day that the whole object of this elaborate secrecy was to hide the fact of her death! She was infinitely more useful alive than dead, Mr. Addison; and they hoped to keep up the solemn farce until—"

"Yes?"

"Until Sir Eric was hanged for the murder of his cousin!"

"Gatton! What do you mean?"

"He is the last of the Coverlys!" answered Gatton simply. "There would be no further danger of any one paying off the mortgage."

"Danger?"

"Exactly. There is some secret at Friar's Park—or at the Bell House—which necessitates the property remaining in the possession of Dr. Damar Greefe—as it has virtually remained since Sir Burnham's death! So much is clear, and although Eric Coverly has persisted in his obstinate silence, one of my assistants who has been at work on the late Sir Marcus's papers made a discovery yesterday, which together with what I had learned from Mr. Hardacre and your code message, brought me down to Crossleys post haste."

"What was this discovery?"

"An invitation from Dr. Damar Greefe, dated only a short time after the death of Sir Burnham, to Sir Marcus, asking him to visit Friar's Park! The doctor explained that the state of Lady Coverly's health made it impossible for her to entertain, but he assured Sir Marcus that she was anxious to see him and to heal any breach which might exist between them. Most significant of all, the Eurasian proposed that Sir Marcus should put up here!"

"At the Abbey Inn?"

"Exactly. Now the 'best room' of the inn is that which you have been occupying—and it is that which Sir Marcus would have occupied had he accepted the doctor's invitation. Listen then: all these clews seemed to point to Friar's Park, but the receipt of your message mentioning one Damar Greefe as being a suspicious party, and asking me to look up his record, quite tipped the scales. I saw, frankly, that you had made a false move, but nevertheless it served my purpose, and I determined to look into the Crossleys end of the inquiry personally, without giving Dr. Damar Greefe reason to suspect that I was in any way associated with the matter.

"I picked up one or two hints from the county police as to the geography as well as the 'notables' of the neighborhood; and the plan which you put into execution to-night, I had adopted last night!"

"What! You visited Friar's Park?"

"I did. But I did not enter through the French window. It never occurred to me that it would be unfastened! I had come provided with a neat set of burglars' tools (and a warrant for use if necessary) and I broke into the kitchen! I found, as you afterwards found, that the place had obviously been deserted for a long time. I was badly puzzled. But my search was more detailed than yours. I climbed up to the top of the tower!"

"To the top of the tower!"

"Yes. I'll tell you what I found there in a minute. But, briefly, beyond learning that the story of the invalid Lady Coverly was a myth, I discovered nothing likely to help the inquiry. I seriously debated the idea of putting Dr. Damar Greefe under arrest; but finally I determined to watch him for a time without showing my hand. I had the good fortune to meet him this morning here at the Abbey Inn! Also, I saw your mysterious lady visitor! Lastly, I got into conversation with the man, Hawkins, who was accompanied by your friend, the mute!

"Leaving this dangerous pair, I made a rush for the Bell House, thinking I saw my opportunity to examine it unmolested. I was too late, though. One of my assistants warned me of the Eurasian's return just as I was about to enter.

"I watched the house all day. But it was not until some time after dusk that the Eurasian came out. He went to Friar's Park—and I followed him!"

"What! You were there to-night!"

"I was! I dogged Dr. Damar Greefe, determined to learn the nature of the business which brought him to Friar's Park at such an hour. I may add that it was only by the merest accident or good luck that I fathomed it after all. I had no idea into what part of the building he had gone, but, knowing that he was somewhere inside, I watched from the shrubbery. In fact, I was still in the grounds when you arrived!"

"Then it was you I saw on the tower!"

"Oh, no, it was not! I had thoroughly examined the tower on my previous visit, and what I found there had puzzled me badly. In fact it was not until your admirable withdrawal from Friar's Park to-night that the horrible explanation dawned upon me ...and I realized that the object of inviting Sir Marcus to Upper Crossleys was to 'remove' him! The first plan failed, of course; he never came. He went back again on duty to Russia, I believe—for a time. But when he returned—a second was adopted, at the Red House. However—the murder-machine erected in accordance with the earlier plan was still there—"

"Where?" I cried in bewilderment.

"On the tower of Friar's Park! It was the appearance of Damar Greefe on the platform of the tower, armed with binoculars, which awakened me to the ghastly truth. The device, never used in the case of Sir Marcus, was not to be wasted, but was to be employed to remove a dangerous obstacle from the conspirator's path! I had left the car near Crossleys, you see, and never in my life have I run as I ran after you to-night!"

"But, Gatton, what did you find on the tower—and what connection exists between the tower and the explosion which occurred here to-night?"

"This: a sort of small howitzer—I think of Krupp's manufacture, but you would be better able to judge than I—is mounted on the platform of the tower! I examined it, Mr. Addison, last night, and like a fool concluded that it had been used at some time for a local celebration and never dismounted! It was trained—as I remembered nearly too late—and laid at a certain elevation in such a way that it was evidently never meant to be moved. Yet at the time the significance of this did not strike me. How the range was found so exactly we shall probably never know; but the truth suddenly burst upon me as you made off through the bushes and as Dr. Damar Greefe came out and began to peer through his glasses—that it was mechanically set in such a manner that it could drop a projectile into the window above the porch of the Abbey Inn!"

"Good God! It's hardly credible!"

"It isn't, I admit. But weather conditions favored him; there wasn't a breath of wind. And that he succeeded is proved by the fact that at the present moment your room below is probably still full of poison gas! Of course, it may not have been a gas-shell; he may have relied, as well he might do, on the burst! But I'm taking no chances. You can well imagine that failing a knowledge of the arrangement on the tower, no explanation of the mystery would ever have been found! A thunder-bolt would be the popular theory, and if any fragments of shell were found who would ever know from where it had been fired?"

"Gatton," I said, "I owe you my life. But why did this fiend try to murder me?"

Gatton smiled.

"I have a theory, Mr. Addison," he replied, "and it is this: I believe he thought that the indiscretion of a certain mysterious lady would bring about his ruin. If I am not mistaken, she has already gone far to put his neck in a halter; and he was determined to nip this latest adventure in the bud by removing the object of her—"

I felt myself changing color, and:

"For heaven's sake say no more!" I interrupted. "It is a gruesome and horrible thought! Yet, perhaps you are right. What must we do, Gatton? These people have rendered the neighborhood uninhabitable for themselves, now, and—"

Dimly to my ears came the sound of a gun-shot.

"And have fled!" cried Gatton, springing up. "Quick! we must chance the gas!"

"Why? What was that shot?"

"A signal! Dr. Damar Greefe and 'the cat' have escaped!"

He raced out across the landing, amid a chorus of frightened inquiries from the inn staff. I followed him into a front room, and:

"This comes of turning my attention elsewhere for half an hour!" he cried angrily. "I seem to be cursed with fools for assistants!"

Throwing up the window, he leaned out. I stood at his elbow; and as I looked I saw a great red glow rising from the distant woods. The sound of a car approaching at headlong speed reached my ears, and at the same moment I saw the headlights.

"Hullo, there!" cried Gatton. "Blythe! Petersham!"

The car stopped, and a cry came back:

"We've lost him, sir!... and the Bell House is in flames!"

"Then the sudden change in the police attitude towards Eric," said Isobel, "is not due to any discoveries which you or Inspector Gatton have made at Friar's Park?"

"That I cannot say," I replied. "We have made certain discoveries as I have already told you, but whilst they distinctly point to some criminal whose identity is not yet fully established, unfortunately I cannot say that in a legal sense they clear Coverly."

Isobel, as I had thought at the first moment of our meeting, looked very tired and had that pathetic expression of appeal in her eyes which had hurt me so much when first it had appeared there on the morning after the tragedy. She was palpably ill at ease, and I had small cause to wonder at this. Although a veiled paragraph (in which I thought I could detect the hand of Gatton) had appeared in the press on the previous day, briefly stating that evidence had been volunteered by Sir Eric Coverly which had led to an entirely new line of police inquiry, the item of news—which had naturally excited wide-spread interest—had never been amplified. Amid the alarms and excursions which had terminated my visit to Upper Crossleys, Gatton I supposed had forgotten to refer to this matter; but I did not doubt that the paragraph was an inspired one issued from Scotland Yard.

My friend's object in circulating this statement was not by any means evident to me, but as I expected to see him later that day I hoped to be able to obtain from him some explanation of his new tactics.

Many hours had elapsed since, with the flames of the burning Bell House reddening the night behind me, and throwing into lurid relief the fir-groves surrounding Dr. Damar Greefe's mysterious stronghold, I had been borne along the road towards London. That Gatton had hoped for much from a detailed search of the Eurasian's establishment, I knew, for I had not forgotten his anger at the appearance of the flames above the tree tops which had told of the foiling of his plans.

Under cover of the conflagration the cunning Eurasian had escaped. Every possible means had been taken to intercept him, and whilst Gatton, inspired by I know not what hopes, had hastened to the burning Bell House, I had set out in the police car in pursuit of Dr. Damar Greefe accompanied by Detective-Sergeant Blythe—upon whom, apparently, the onus of the fiasco rested.

In despite of these measures, the hunted man had made good his retreat; and Blythe and I had entered the outskirts of London without once sighting the car in which Damar Greefe had fled.

No communication reached me on the following morning, and I found myself, consumed with impatient curiosity, temporarily out of touch with Gatton. Then, shortly after mid-day, came a telegram:

"Endeavor induce Sir Eric come to your house eight to-night. Will meet him there. Gatton."

Welcoming any ground for action—since to remain passive at such a time was torture—I called at once at Coverly's chambers. He was out. But I left an urgent written message for him, and in the hope of finding him with Isobel, hurried to her flat. He had not been there that day, however; and now I could only hope that he would return to his rooms in time to keep the appointment. For that Gatton had some good reason for suggesting the meeting I did not doubt.

Gatton and I were now agreed that Dr. Damar Greefe, if not directly responsible for the death of Sir Marcus, at least had been an accessory to his murder. At any rate he had shown his hand; firstly, in the attempted assault upon myself by his Nubian servant and secondly, by the devilish device whereby he had propelled some sort of gas projectile (for this we now knew it to have been) from the tower of Friar's Park into my room at the Abbey Inn. I had, then, become obnoxious to him; he evidently regarded my continued existence as a menace to his own.

Two explanations of his attitude presented themselves: one, that my inquiries had led me daily nearer to the heart of the mystery; or, two, that the doctor's mysterious associate, the possessor of the green eyes, had adopted an attitude towards myself which the Eurasian had counted sooner or later as certain to compromise him. In short, whilst it was sufficiently evident to me that these mysterious people residing at Upper Crossleys were the criminals for whom New Scotland Yard was searching, no definite link between their admittedly dangerous activities and the crime we sought to unravel, had yet been brought to light.

On the other hand, whilst it was not feasible to suppose that any relationship existed between Sir Eric, the new baronet, and the Eurasian, or the woman associated with the Eurasian, I was quite well aware that, equally, there was no evidence to show that such an association did not exist.

I longed to be able to offer some consolation to Isobel, who at this time was passing through days and nights of dreadful apprehension; but beyond imparting to her some of my own personal convictions, I was unable to say honestly that the complicity of Coverly in the murder was definitely and legally disproved.

"If only he would break his absurd silence," she said suddenly. "This ridiculous suspicion which still seems to be entertained in some quarters would be removed of course; but his every act since the night of the tragedy has only intensified it."

She sat facing me on the settee, her hands locked in her lap, and:

"Do you refer to any new act of his," I asked, "with which I am not at present acquainted?"

She nodded slowly.

"Yes," she said; "but I can only tell you in confidence, for it is something which Inspector Gatton does not know."

"Please tell me," I urged; "for you are aware that I have no other object but the clearing of Coverly in the eyes of the police and the public."

"Well," she continued, with hesitation, "last night he lodged with me a copy of a declaration which he assured me cleared him entirely. But he imposed an extraordinary condition."

"What was that?" I asked with interest.

"It was only to be used in the event of the worst happening!" she said.

"What do you mean? In the event of his being put on trial for murder?"

Isobel nodded.

"I suppose so," she said sadly; "it seems madness, doesn't it?"

"Absolute madness!" I agreed. "If he is in a position to establish an alibi why not do it now and be done with the whole unsavory business?"

"That is exactly what I pointed out to him, but he was adamant on the matter and became dreadfully irritable and excited. I did not dare to press the point, so of course—" She shrugged her shoulders resignedly.

Was it a selfish joy, I wonder, which possessed me as I noted the restrained impatience with which Isobel spoke of Coverly? I suppose it was, and perhaps it was even indefensible; yet I record it, desiring to be perfectly honest with myself and with others. Nevertheless, in the near future I was to regret the sentiments which at that moment I entertained towards Coverly. But how was I to know in my poor human blindness that his innocence would soon be established in the eyes of the world by other means than the publication of the statement which he had so strangely placed with Isobel?

Since, excepting the telegram, no communication had reached me from Gatton, I could only assume that he had discovered nothing in the ruins of the Bell House of sufficient importance to justify a report. Doubtless he had reported to New Scotland Yard, but that his discoveries, if any, had not resulted in an arrest, was painfully evident.

My latest contribution to the Planet had been in the nature of a discursive essay rather than an informative article, although I had enlivened it with some account of my experiences at Upper Crossleys. But at the moment that I had set pen to paper I had realized the difficulty of expressing, within the scope of a newspaper contribution, the peculiar conditions which ruled in that oddly deserted village. And at Gatton's request I had been most guarded in my treatment of the two abortive attempts made upon my own life by the Eurasian doctor.

The appeal in Isobel's eyes, as I have said, was very difficult to resist, but after all I had little substantial consolation to offer; and in the circumstances I shall be understood, I think, when I say that it was with an odd sense of relief that I finally took my departure from her flat. To long for the right to comfort a woman as only a lover may do, and to suspect that this sweet privilege might have been his for the asking, is a torture which no man can suffer unmoved.

Anticipating, almost hourly, a further message from Gatton, I went first to the Planet offices, but although I lunched at the club and returned later, no news reached me there; whereupon, I proceeded to my cottage. As I walked down the high-street of the onetime village, passing that police-box at which (so far as my part in it was concerned) the first scenes of the drama actually had been laid, I was seized with wonder on reflecting that all these episodes, strange and tragic, had been crowded into so short a space of time.

An officer was on duty there as on the night when I had first made acquaintance with the green eyes of the woman of mystery; but I did not know the man and I walked on deep in meditation, until, arriving at the Red House, other and dreadful reflections were aroused by the sight of that deserted building.

There were no spectators to-day, for the first excitement aroused by the crime had begun to subside, and I did not even notice a constable posted there. Whereby I concluded that the investigations at the Red House had been terminated and that no more was hoped for from an examination of those premises.

Coates was awaiting me as I entered my cottage with the news that Inspector Gatton had telephoned an hour before from Crossleys, confirming his telegram and stating that he would call immediately he arrived in London. This was stimulating, and I only regretted that I had not been at home personally to speak to him. Then:

"Sir Eric Coverly also rang up, sir," continued Coates, "at about three o'clock and said that he would be calling this evening at eight in accordance with your request."

I looked at the military figure standing bolt upright just within the doorway.

"Good. Is that all?" I asked.

"That was all the message, sir," he reported.

I walked into the study in a very thoughtful mood, and from the open window contemplated that prospect of tree-lined road, now for ever to be associated in my mind with the darkest places in the tragedy in which I had so strangely become involved.

Gatton, I knew, entertained a theory that the selection of the Red House for the dreadful purpose for which it had been employed, was not the result of any mere accident, but was ascribable to the fact that the place was conveniently situated from the point of view of the assassin. In short, he had an idea that the London headquarters of the wanted man, whom we had now definitely invested with the personality of Dr. Damar Greefe, was somewhere within my immediate neighborhood!

It was a startling conclusion and one which rested, as I thought, upon somewhat slender premises; but nevertheless I found it disquieting. And recognizing how the more sinister manifestations of that singular green-eyed creature (whom I could never think of as a woman, nor indeed regard as anything quite human) were associated with darkness—a significantly feline trait—I confess to a certain apprehension respecting the coming night. This apprehension was strengthened no doubt by my memories of Gatton's last words as I had been on the point of setting out from Upper Crossleys.

"With their Friar's Park base destroyed, Mr. Addison," he had said, "they will be forced to fly to that other abode, at present unknown, from which I believe they conducted the elaborate assassination of Sir Marcus. The only alternative is flight from the country, and the mechanism of the C.I.D. having been put into motion, this we may regard as almost impossible—especially in view of the marked personality of Dr. Damar Greefe. Of course," he had added, "they may have some other residence of which we know nothing but I incline to the idea that they will make for London."

That the published paragraph relating to Eric Coverly's alleged evidence was in some way associated with this theory of Gatton's I knew, but of the soundness of his theory I had yet to learn.

Since (as Isobel had that day informed me) the document lodged with her was a profound secret from all, Carton's inspired paragraph could have been no more than a shot in the dark; and the fact that it had hit the mark one of those seeming coincidences which sometimes rest upon mere chance, but which rested, in this case upon a process of careful reasoning. The Inspector was certain, as I was certain, of Coverly's innocence, and he had credited him with an alibi because he knew that if he would but consent to break his inexplicable silence, he was in a position to establish one. Why he had forestalled Coverly I knew not.

I made a poor and hasty dinner, for I was too excited to eat, and returning to the study, I crossed to the bookcase and took down Maspero's "Egyptian Art." I idly glanced again through those passages which Gatton had copied into his note-book—the passages relating to the attributes of Bâst, the cat-goddess. My mind rested particularly, I remember, upon the line, "she plays with her victim as with a mouse."

Stifling a somewhat weary sigh, I returned the book to its place and lingered looking out of the open window into the deepening dusk. Mentally my mood was a restless one, but it did not reflect itself physically; for I stood there leaning against the window whilst a procession of all the figures associated with the "Oritoga mystery" raced through my mind.

And presently as I stood there contemplating a mental image of the Eurasian doctor, I heard the telephone bell ring. The sound aroused me in a moment, and walking out into the little ante-room in which the instrument was placed, I took it up—anticipating Coates, who had immediately come in from the garden where he was engaged at the time.

"Hello!" I said.

A voice with which I was unfamiliar, a man's voice speaking rather thickly, replied:

"Is that Mr. Addison?"

"Yes."

"I have just arrived from Crossleys with Inspector Gatton. He requests me to ask you to meet him by the police-box at the corner of the high street immediately."

"Very good," I said. "I will come."

"And," continued the voice—"could you spare Coates with the car for an hour?"

"Certainly," I replied. "For what do you want him?"

"If he will take the car to Denmark Hill Station and be there by a quarter past eight," continued the voice, "Detective-Sergeant Blythe will meet him. There is a large box," he added, "which Inspector Gatton wishes to have taken to your house."

"Very well," I said. "Coates will start in ten minutes' time, and I will come along immediately to meet Inspector Gatton."

I replaced the telephone upon the little table and went out into the garden, whither my man had returned.

"Coates," I said, "get out the Rover."

Coates immediately ceased his gardening operations and stood upright in an attitude of attention.

"Very good, sir."

"You will just have time to get ready at the garage and return here to admit Sir Eric Coverly at eight o'clock. I am going out, now, to meet Inspector Gatton. But inform Sir Eric that I shall be back in a few minutes. Show him into the study and make him comfortable. You will then proceed in the Rover to Denmark Hill Station. You will meet there a man with a box—a detective from Scotland Yard who will make himself known to you. His name is Blythe. You have to bring the box back here."

"Very good, sir," repeated Coates.

And as he entered the house he was already stripping off the old shooting jacket which he wore in the garden. For my part I slipped a light top-coat over my somewhat untidy house attire, and taking my hat and a stick, stepped quickly out along the road in the direction of the village street. A brisk walk brought me to the little sentry-box under the trees. But Gatton was not to be seen. Indeed, with the exception of several ordinary pedestrians who were obviously returning from the city to their homes (all of whom I scrutinized, thinking that Coverly might come this way) and the constable on duty at the point, there was no one about who looked in the least like either of my expected visitors.

Having waited for some ten minutes unavailingly, I spoke to the man in the box.

"Good evening, constable," I said; "I expected to meet a friend here—Inspector Gatton, of Scotland Yard—you may know him?"

"I know of him quite well, sir," answered the constable, "and should recognize him if I saw him. But he has not been here this evening."

"You have seen no one hanging about who might have been sent by him?"

"No one, sir."

"Strange," I muttered; then: "My name is Addison, constable," I said, "and if any one should ask for me will you direct him to proceed to my house?" And I gave the man instructions respecting its whereabouts.

"I will," answered the constable; and wishing him "good night," I retraced my steps, curious respecting the matter, but not apprehensive as I well might have been—and with no glimmering of the ghastly truth penetrating to my mind.

I was about half-way on my return journey when I heard a car racing along the road behind me, and as it came nearer I detected the fact that it was slowing down. Ere I could turn:

"Hi! Mr. Addison!" hailed a voice.

I stopped, turned round, and there was Gatton leaning out of the car and staring towards me through the deepening dusk.

"Why, Gatton!" I said, walking up to him—"I waited more than ten minutes for you, and then gave it up."

"Waited for me?"

"Yes, by the police-box."

He stared in evident wonder at me and then at the police chauffeur who drove the car.

"Whatever prompted you to do that?" he said. "Coates must have given you the wrong message. I said I would come to the house for you, not meet you in the street."

Still I remained dense to the truth, and:

"I know you did," I replied. "I refer to the second message."

"I sent no second message."

"What!"

"Get in," cried Gatton shortly; "this wants explaining."

I stepped into the car, and as it moved onward again I explained to the Inspector what had taken place. As I talked I saw his expression grow darker and darker, until finally:

"There's something wrong!" he muttered.

"Then you did not inspire the message?"

"I know nothing whatever about it. At the time you received it I was on my way from Crossleys. I have been traveling for the last hour and a half."

I stared at him very blankly. The object of such a communication was difficult to imagine, and I knew of nothing incriminating in my possession, which might have tempted the assassin to lure me from the house whilst he obtained possession of it.

In ever-growing excitement I watched the houses slipping behind us as we swept along. Then we came to the tree-lined expanse of road immediately leading to the cottage. As the car stopped, I leaped out quickly, Gatton close upon my heels, and ran up the path to the door.

From certain indications with which I was familiar, I observed that Coates was out, whereby I concluded that he had set off to meet the mythical "man with a box." Not without apprehension I inserted the key in the lock and opened the door.

As I did so, I beheld a most singular spectacle.

The careful Coates had closed all the windows as usual before quitting the house, so that there was comparatively little draught along the corridor. But as the door swung open I perceived a sort of gray fog-like vapor floating over the carpet about a foot in depth and moving in slightly sinuous spirals upward towards the opened door!

At this phenomenon I stared in speechless astonishment; for whilst it resembled steam or the early morning mist which one sometimes sees upon the grass in hot weather, I was wholly at a loss to account for its presence inside my cottage!

"Good heavens!" cried Gatton, and grasped me by the arm with so strong a grip that I almost cried out. "Look! Look!"

"What the devil is it?" I muttered; and turning, I stared into his face. "What can it be?"

"Stand back," he said strangely, and pulled me out into the porch. "Do you notice a peculiar smell?"

"I do—a most foul and abominable smell."

Gatton nodded grimly.

"God knows what has happened here since you left," he said; "but of one thing I am sure—you must certainly bear a charmed life, Mr. Addison. There has been a third attempt at your removal!"

This choking smell which now rose to my nostrils had in it something vaguely familiar, yet something which at that place and that time I found myself unable to identify; but:

"We shall have to open the windows!" rapped Gatton.

Suiting the action to the word, he took out his handkerchief, and holding it to his nostrils went running along the corridor, his feet oddly enveloped in that mysterious mist. A moment later I heard the bang of a swiftly raised window, then another, and:

"Stand clear of the door!" called a muffled voice.

A moment later Gatton came racing back again, coughing and choking because of the fumes which arose from that supernatural fog carpeting the passages.

The chauffeur now appeared upon the path leading from the gate to the porch, but:

"Stay by the car!" ordered Gatton. "Don't move without instructions."

I scarcely noted his words. For I was watching the gray fog. In the dusk I could see it streaming out, that deathly mist, and creeping away across grass and flower-beds, right and left of the door.

"Give it a chance to clear," said Gatton; "I fancy one good whiff would finish any man!"

Even as he spoke the words the nature of this vapor suddenly occurred to me, and:

"The Abbey Inn!" I whispered. "The Abbey Inn!"

"Ah!" said he—"you've solved the mystery, have you? But can you explain how this stuff comes to be floating about the floor of your house?"

"I cannot," I confessed. "But at all costs we must go in. We must learn the worst!"

"Yes, we'll risk it now," said the Inspector.

Close together we entered and made our way towards the study. As we passed the door-way of the ante-room in which the telephone was placed. I glanced, aside, and thereupon:

"My God, Gatton!" I groaned. "Look!"

He pulled up and the two of us stood, horror-stricken, rooted to the spot, looking into the little room.

I have said that Coates invariably closed the windows before leaving the house, but here the window was open. Prone upon the floor was stretched the figure of a man!

He wore a light overcoat, and his hat lay under the telephone table—where it had evidently rolled at the moment of his fall. The poisonous smell was more apparent here than elsewhere; and looking down at the prone figure, the face of which was indiscernible because of the man's position:

"Why, Gatton!" I said in an awed whisper—"look!... he was speaking to some one!"

"I'm looking!" replied Gatton grimly.

Grasped rigidly in his left hand the fallen man held the telephone!

"We want gas-masks for this job," said the Inspector.

His words were true enough. I had already recognized the odor of the foul stuff. It was identical with that which, as we had come down from the upper floor of the Abbey Inn, had proceeded from the room wherein the mysterious shell had exploded. In a word my cottage was filled with some kind of poison-gas!

"We must risk it, anyway," said Gatton, "and find out who it is."

I nodded, sick with foreboding. Stooping swiftly, he succeeded in turning over the prone figure, whereupon I quite failed to restrain a hoarse cry of horror....

It was Eric Coverly!

The fume-laden room seemed to swim around me as I looked down at the dreadfully contorted features over which was creeping that greenish tint which had characterized the face of Sir Marcus as I had seen it on the morning of the body's recovery from the hold of the Oritoga.

"Drag him out," said Gatton huskily; "he may be alive."

But even as we bent to the attempt, both my companion and I were seized with violent nausea; for the wisps of gray mist which still floated in the air were nevertheless sufficiently deadly. However, we succeeded at last in dragging Eric Coverly into the passage. Here it became necessary to detach the telephone from the death-grip in which he held it.

I turned my head aside whilst Gatton accomplished this task; then together we bore Coverly out into the porch. At this point we were both overcome again by the fumes. Gatton was the first to recover sufficiently to stoop and examine the victim of this fiendish outrage. I clutched dizzily at an upright of the porch, and:

"Don't tell me he's dead," I whispered.

But Gatton stood up and nodded sternly.

"He was the last!" he said strangely. "They have triumphed after all."

The man who had driven the car and who now stood in a state of evident stupefaction looking over the gate, where he had been warned to remain by the Inspector, came forward on seeing Gatton beckoning to him.

"Notify the local officer in charge and bring a doctor," said Gatton. He turned to me. "Which is the nearest?"

Rapidly I gave the man the necessary instructions and he went running out to the car and soon was speeding away towards the house of a local physician.

I find it difficult to recapture the peculiar horror of the next few minutes, during which, half-fearful of entering the cottage, Gatton and I stood in the little sheltered garden adjoining the porch looking down at the body of this man who had met his end under my roof, in circumstances at once dreadful and incomprehensible.

Tragically, Eric Coverly was vindicated; by his death he was proved innocent. And by the manner of his death we realized that he had fallen a victim to the same malign agency as his cousin.

I have explained that my cottage stood in a strangely secluded spot, although so near to the sleepless life of London; and I remember that throughout the period between the departure of the man with the car and his return with the doctor and two police officers whom he had brought from the local depot, only one pedestrian passed my door and he on the opposite side of the road.

How little that chance traveler suspected what a scene was concealed from his eyes by the tall hedges which divided the garden from the highroad! It was as the footsteps of this wayfarer became faint in the distance, that suddenly:

"Come along!" said Gatton. "We might chance it now. I want to get to the bottom of this telephone trick."

We returned to the door of the ante-room, and side by side stood looking down at the telephone which had only been extracted from the grip of the dead man with so much difficulty. The Inspector stooped and took it up from the floor. The deadly gray mist was all but dissipated now, and together we stood staring stupidly at the telephone which Gatton held in his hand.

To all outward seeming it was an ordinary instrument, and my number was written upon it in the space provided for the purpose. Then, all at once, as we stepped into the room, I observed something out of the ordinary.

I could see a length of green cable proceeding from the wall-plug out through the open window. The cable attached to the instrument which Gatton held did not come from the proper connection at all, but came in through the window, and was evidently connected with something outside in the garden!

"What does this mean, Gatton?" I cried.

Evidently as deeply mystified as I, Gatton placed the telephone on the little table and fully opening the window, leaned out.

"Hullo!" he cried. "The cable leads up to the roof of the tool-shed!"

"To the roof of the tool-shed!" I echoed incredulously.

But Gatton did not heed my words, for:

"What the devil have we here?" he continued.

He was hauling something up from the flower-bed below the window, and now, turning to me, he held out ... a second telephone!

"Why, Gatton!" I cried, and took it from his hand, "this is the authentic instrument! See! It is connected in the proper way!"

"I see quite clearly," he replied. "It was simply placed outside, whilst a duplicate one was substituted for it. I observe a ladder against the shed. Let us trace the cable attached to the duplicate."

The ladder was one used by Coates about the garden; and now, climbing out of the window, Gatton mounted it and surveyed the roof of the lean-to which I used as a tool-shed.

"Ha!" he exclaimed. "A gas cylinder!"

"What!"

He fingered the green cable.

"This is not cable at all," he cried; "it's covered tubing! Do you see?"

He descended and rejoined me.

"You see?" he continued. "A call from the exchange would ring the bell in the ante-room here. This devilish contrivance"—he pointed to the false telephone—"is really hollow. The weight of the receiver hermetically closes the end of the tube, no doubt. But any one answering the call and taking up the duplicate instrument would receive the full benefit of the contents of the cylinder which lies up there on the roof!"

"My God, Gatton!" I muttered. "The fiends! But why was the contrivance not removed?"

"They hadn't time," he said grimly. "They had not counted on the death-grip of the victim!"

I heard a car come racing up to the gate, followed by the sound of many excited voices.

"At last we know where the gray mist came from," I said, as Gatton and I walked through the cottage to meet the new arrivals.

"We know more than that," he retorted. "We know how Sir Marcus died!"

"Gatton!" I cried excitedly, as we approached a group waiting in the porch—"do you mean—"

He looked at me grimly.

"I mean," he said slowly, "that I have not forgotten the gas-plug in the wall of that recess in the supper-room at the Red House! The only thing I was doubtful about (the means by which the victim was induced to admit the gas into the room) is now as clear as daylight."

"You are right, Gatton," I agreed. "The same trick has succeeded twice."

"The same trick, as you say, Mr. Addison; with one trifling variation, a device which would only suggest itself to such a brain as that of—"

"Dr. Damar Greefe!" I cried.

"I believe you are right."

And now fell an awesome silence; for whilst Gatton and I stood bare-headed, the unfortunate Eric Coverly was being carried out to the waiting car; and even as I turned my eyes away in horror from that spectacle, I was endeavoring to frame the words in which I should acquaint Isobel with this second ghastly tragedy.

Here, indeed, was a new development of "the Oritoga mystery"; and so queerly does the mind depart from the actualities at such a moment that I found myself thinking, even whilst Gatton was talking to me, of the bold head-lines which would greet readers of the press in the morning—and of the renewed excitement which would sweep throughout the length and breadth of the land when this dreadful alibi was proven.

Over the details of that gruesome tragedy I feel myself compelled to pass lightly, for even now the horror of it remains with me. The fumes of the poisonous gray mist lingered for hours in the house; and there were official visitations, testimonies and attestations, and the hundred and one formalities which invariably accompany such a tragedy but which I need not deal with in detail here.

Coates returned with the Rover, just as the body of the victim was being removed, and his account of what had occurred was simple enough, and followed the lines which we had anticipated. He had locked up and then gone to the garage for the car as I had directed him to do, returning to the cottage in time to admit Eric Coverly, whom he showed into the study, having informed him that I should be back in less than ten minutes. He had then proceeded to Denmark Hill railway station only to find, as I had found, that the appointment was a hoax and "the man with a box" a myth.

"You see," said Gatton, "the scheme of the plotter was simply this: to get Coates out of the way for a long enough time to allow the substitution of the telephone to be accomplished. The fact that Coates had closed the windows before leaving the house didn't interfere very much with the scheme. It's an old-fashioned catch on the ante-room window, and I have seen the marks upon the brass-work where it was forced from the outside with the blade of a knife. For the person who opened the window to take out the real telephone and put the other in its place was easy; and all that remained was to lift the gas-cylinder on to the shed and partly reclose the window as we found it. Coates, even if he had troubled to look, would not have noticed any difference in the dusk. It is the next move, however, which I find most interesting."

Gatton spoke with repressed excitement, and:

"What do you mean by 'the next move'?" I asked.

"Well," he replied, "we have good evidence to show that the assassin possesses an almost Napoleonic capacity for working by the time-table. Witness the employment of Constable Bolton in the Red House affair—which showed that our man was perfectly acquainted with the movements of the officer on that beat and timed his scheme accordingly. Very well ... having laid the telephone trap in your ante-room—did our man hurry away and make the call in person, which brought Coverly to the 'phone?—or did he remain watching the house and give the signal to some one else to do it?"

"I cannot imagine, Gatton. Nor does the point strike me as important."

"No?" said Gatton, smiling triumphantly. "Then I must explain. Whereas, in the Red House, the scheme worked automatically—for the time of Sir Marcus's arrival was fixed—in the present instance, some one had to watch for your return from the mythical appointment!"

"For my return?"

"Unquestionably! This scheme was arranged for your benefit, Mr. Addison. Unknowingly, poor Coverly saved you from a dreadful fate at the price of his own life! You see, they did not know that Coverly was coming here! Now, it will not have escaped your attention that he wore a soft felt hat, a light overcoat, and carried a black cane. So did you when you went out to keep the appointment made by the assassin!"

He paused, staring at me hard, and:

"Whoever was watching for your return," he said solemnly, "mistook Coverly for you! The moment that Coates drove away, the signal was given. It must have been. We were back here a few minutes later, Now do you see?"

"I do not, Gatton! What are you driving at?"

"At this: The telephone call must have been made from somewhere in the immediate neighborhood! There wasn't time to do it otherwise. And there is no public call office within a mile which is open after seven o'clock!"

"Good heavens!" I cried. "At last I understand!"

Gatton looked at me, smiling in grim triumph; and:

"Dr. Damar Greefe has a residence somewhere within a quarter-mile radius of this house!" he declared. "He has betrayed himself! Then—look here."

Unscrewing the front of the mouthpiece of the false telephone, he took out the strip of cardboard upon which my number was written, turned it over ... and there upon the back was another number!

"Just look up Dr. Brown-Edwards," he said. "He was the last occupant of the Red House, and may still be in the book."

Grasping the purpose of his inquiry, excitedly I did as he directed; and there sure enough the number appeared!

"The identical instrument that was used at the Red House!" cried Gatton. "Note the artistic finish with which even the correct exchange numbers are looked up!"

I sank back in my chair, silent, appalled at the perverted genius of this fiend whom we were pitted against in a life-or-death struggle. But presently:

"What was the object of the opening and closing of the garage doors at the Red House?" I asked, almost mechanically.

"Simple enough," Gatton replied. "Whereas here the telephone was installed, so that the bell could be rung by some one merely calling up your number—and the ringing stopped by the caller telling the exchange he had made a mistake—in the Red House, as I have discovered, the 'phone had been disconnected shortly after Dr. Brown-Edwards left the place."

"Then the opening and closing of the doors was merely a device for ringing the bell?"

"Yes. The opening of the first door set it ringing and the opening of the second probably stopped it. Mr. Addison," he stood up, resting his hands upon the table and regarding me fixedly—"we enter upon the final battle of wits: New Scotland Yard versus Dr. Damar Greefe and the green-eyed lady of Bâst. Regarding the latter—there is a very significant point."

"What is that?"

"The 'voice' on this last occasion was that, not of a woman, but of a man."