I had ordered my Chinese boy to wake me at eight. In one corner of the Grand Square was a beautifully fitted gymnasium with a swimming-bath adjoining. I proposed three-quarters of an hour's vigorous exercise before dressing.

At it happens I generally wake more or less at the time I want to. This morning, however, it was half-past eight. There was no sound of Chang whatever. I got out of bed, put on a sweater, Norfolk jacket, flannel trousers, and tennis shoes – I had sent for a portmanteau of clothes from the "Golden Swan" – went across the hall and let myself out into the gardens.

Then I hesitated in amazement. A thick, heavy, impenetrable mist hid everything from sight. It seemed as solid as wool. One literally had to push one's way through it, and when I say that I couldn't see more than a yard before my face, I mean it in the strict sense of the words. Still, I remembered that I have a good sense of topography, and I was quite confident that I could find my way to the central Square, where there would be sure to be people about whom I could ask.

From my front door there was a good hundred and twenty yards of wide gravel path to the Palacete Mendoza. I sprinted up this in less than twenty seconds I should say, and then warily turned into the palm-tree grove – the great sheets of plated glass on either side of the way were in place now, but I knew where I was because of the different quality of the ground, which was here paved with wood blocks. Soon, a faint gray mass to my right, the palace itself loomed up, but the blanket of mist was too thick for me to discern windows or doors. One could see nothing but the gray hint of mass.

The curious thing was that one could hear nothing either. That had not struck me as I did my sprint, but now it did, and most forcibly. Of course there was no sound of wind – had there been any wind we should not have been buried in the very heart of this fog – thicker and more sticky than anything I had ever experienced in the Alps themselves. But there were no sounds of occupation such as an extensive place like the City might have been expected to produce at this hour, and in fact, as I realized, did produce, when I remembered yesterday. The place was never noisy. It was a haunt of peace if ever there was one. But the sound of gardeners and servants going about their daily toil, the distant throbbing of an engine perhaps, a subdued voice giving an order, the plashing of fountains, and the strains of music, all these were utterly and entirely absent. It was as though the mist killed not only vision but hearing also. I might have been on the top of Mont Blanc.

"What little town by harbor or sea-shore
Is empty of its folk this pious morn?"

I quoted to myself with a laugh, just as I entered the arched tunnel wide enough for two coaches to be driven under it abreast, which I knew led to Grand Square.

I laughed, and then quite suddenly all laughter went out of me. I couldn't explain it at the moment, but the mist, the loneliness, my whole surroundings, seemed quite horrible.

Surely something had passed me? I called out, and my voice seemed like the bleating of a sheep. Of course, it was illusion. My nerves had suddenly gone wrong. But, honestly, I felt that there was something nasty in the atmosphere, nasty from a psychic point of view I mean. There are moments when the human soul turns sick and retches with disgust, and I experienced such a moment now. I think it was exactly then that I knew, though I wouldn't allow myself to believe it, that I knew inwardly all was not well. I walked on and my india-rubber shoes seemed to make a sly, unpleasant noise – it was the only one I heard even now.

I could see nothing, I was quite uncertain of where I was, so I turned and walked straight to the right until, from the impact of the air upon my face, I knew that I was within a yard or so of some building. This was correct. My hand touched what seemed like stonework, and glancing up I became aware that a building rose high above.

I followed this along, keeping my hand on the stone, moving it round projecting buttresses and going with great caution. This insect-like progression seemed to be endless. I took out my watch, which I had shoved into the breast pocket of my Norfolk jacket. It was nearly nine o'clock, and not a single sound!

A second or two afterwards I came to a balustrade, felt my way along it, and found that I was at the foot of a broad flight of steps. There seemed something vaguely familiar here, and as I ran up them I began to be sure that I was at the library. I knew that Pu-Yi lived somewhere on the premises and I felt all over the great iron-studded door until I came to the small postern wicket through which one generally entered. This was locked, but a bell-pull of wrought iron hung at the side and I pulled at it lustily for a considerable time.

It opened with a jerk and Pu-Yi stood there in his skull cap with the coral button on the top and wrapped in a bear-skin robe.

"Thank goodness I've found some one," I said. "I've lost my way. I was going to the gymnasium, to exercise a little and then have a swim. My boy didn't turn up so I came out by myself."

"Come in, come in, Sir Thomas," he said, peering out at the white curtain. "What a dreadful morning! I've been here some months now, but I have never seen it so bad as this. I daresay it will blow off by nine o'clock or so when the sun gets up."

"It's nine o'clock now," I told him.

He started violently.

"Then my servant also is at fault," he said. "I ordered my coffee for eight. I was reading far into the night and must have overslept myself. This is very curious."

"Do you know, I don't quite like it, Pu-Yi. I've come all the way from the pavilion in the Palace gardens and haven't heard the least sound of any sort whatever."

We passed through a lobby and entered the great library, which was cold and gray as a tomb.

Pu-Yi snapped at a switch, then at another. Nothing happened.

"The electric light is off!" he cried. "What an extraordinary thing!"

"Mine wasn't," I said. "I got out of bed and dressed by it."

He did not reply, but took down the speaking part of a telephone and turned the handle of the box. In that gray light his thin face, with its expression of strained attention, was one I shall not easily forget.

He turned the handle again, angrily. Again an interval of silence.

"The telephone is out of order," he said, and we looked at each other with a question in our eyes.

"Well, I'm confoundedly glad I've found you," I said.

"We must look into this at once, Sir Thomas. I can find my way perfectly well to one of the lifts at the other end of the Square. We must summon assistance. One moment." He vanished for a minute and returned with something cool and shining which he pressed into my hand. It was a venomous ten-shot Colt automatic. "You never know," he whispered.

We hurried across the great Square, passing by the central fountain basins, though the fountains were not playing, which added to our uneasiness. Everything was deathly still until we came to the little lift pavilion. I half expected the thing to stick, but it glided down easily enough. As if my companion read my thoughts he said:

"All these small lifts are not electrical, but are worked by hydraulic power, the station for which is in the City and not below on the earth."

I shall never forget the extraordinary sight as we stepped from the lift. The mist here was nothing like so thick as it was above. This was owing to the fact that a hundred feet above our heads there was the immense ceiling of steel plates and girders upon which the City rested. As I said before, on all three sides this second service City was open to the air, but not above. Consequently the mist moved in tall white shapes like ghosts; it entirely surrounded one group of huts and left another great vista of buildings plain to the eye. Here a gaudily painted gable thrust itself out of the white sheet; there, through a proscenium of clinging wool, one saw the gray interior of a machine-room. A chill twilight brooded everywhere. There wasn't a single lamp burning, and from one end to the other lay the desolation of utter silence.

I leant against the jamb of the lift door, and, despite the cold, the sweat ran down my body in a stream.

Pu-Yi raised a thin arm over his head and it seemed to clutch crookedly at the somber panoply aloft.

A high, thin wail came from his parted lips and went mournfully away down the deserted streets and empty habitations.

For myself, I had been so stunned that I couldn't think, but my friend's despairing call seemed to jerk some cog-wheel within the brain and start again the mechanism of thought.

I gripped him by the shoulder.

"There isn't a soul here," I rasped out. "What does it mean, what on earth does it mean?"

"There should be three hundred at least," he answered.

I broke away at a run, flung open the first door I came to and peered in. It was some sort of a sleeping-room, there were bunks and couches all around the walls. Each one of them was empty. I had time to see that, and also that a stand of short carbines and cutlasses was full of weapons.

Then I had to back out quickly for the late inmates had left an odorous legacy behind them.

Pu-Yi faced me.

"That was one of the patrol rooms," he said.

Then I remembered our coming two days ago.

"Mulligan!" I cried. "Nobody could get here except through the guard-room, nobody could leave here except through that, could they?"

"Not unless they threw themselves from the side of the tower."

"Well, it's quite impossible to believe that three hundred people have committed suicide during the night without a sound being heard. Quick! let's get to the bottom of this."

Pu-Yi led. He didn't seem really to run, only to glide along the ghostly streets and passages. But I had hard work to keep up with him, all the same. My mouth felt as if it had been sucking a brass tap. The most deadly fear clutched at my heart – that noiseless, pattering run through the deserted town in the air, accompanied always by the mouthing, gibbering ghosts of the mist, was appalling.

We dashed down the last corridor and were brought up by a stout door. Pu-Yi bent down to the handle, turned it gently, and – it opened.

We tiptoed into that room. Directly I was over the threshold, the spiritual odor of death, of violent death, came to me.

A fire of logs was still burning redly upon the hearth. For the rest the room was lit only by its skylight, through which filtered a dirty and opaque illumination which was only sufficient to give every object a shape of the sinister or bizarre. The red glow from the fire glistened upon the polished screen of steel which divided the room into two portions. And it also fell, redly, upon something else.

This was the corpse of Mulligan.

It was seated in a chair which had been pulled up to the screen with its back towards it, as if in mockery and derision of its power to keep it.

He had been strangled by a yard of catgut, twisted, tourniquet-fashion, by a piece of stick at the back of the neck. The catgut had sunk far into the flesh, reducing the neck to less than half its ordinary size, and the great staring head hung down upon one shoulder.

One of the logs in the grate fell with a crackle of sparks. For the rest, dead silence.

"They have come," Pu-Yi said simply.

"But what has happened?" I whispered, my throat was so dry that the sound was like the rustling of paper.

"I shall know soon. I am going to find out. There is not a minute to lose. Can you, dare you, wait here – "

I nodded and he was out of the room in a flash. Upon the dead man's table was the usual array of bottles and glasses. I took some brandy and gulped it down and my brain cleared instantly. There was a little touch of infinite pathos even in this hideous moment, for by the side of an empty glass I saw a string of beads with a little metal crucifix. The Irishman, a Roman Catholic of course, must have been saying his prayers some time before he met his end. Somehow the thought comforted me and gave me power to act. I found a knife, and cut the bonds that tied the giant to the chair. I lowered him reverently to the floor and finally severed the horrible ligature around his throat. An examination of the steel door in the screen of bars showed that it was securely locked, but the bunch of keys which the dead man usually carried upon a chain was no longer there – the end of the chain dangled from his trousers pocket.

While I was doing these things a most deadly apprehension was standing specter-like by my side and plucking with wan fingers at my sleeve. What had happened, what might even now be happening at the Palacete Mendoza?

Pu-Yi whirled into the room. He made no noise, it was as though a dried leaf had been blown in by the wind. His face was transformed. Every outline was sharpened, and the color was changed until it bore the exact resemblance to a mask of green bronze. In its frozen immobility it was dead, yet awfully alive, and the eyes glittered like little crumbs of diamond.

"Well?"

"I know how it has been done. It is very clever, very clever indeed. Let me tell you that all the power cables connecting us with below have been scientifically cut. We can neither telephone down to the Park nor can we descend to it in one of the lifts. We are isolated up here in the clouds."

"But the men, the staff?" I gasped, and then I stepped back, staring down at his hands. They were all foul and stained with blood.

"Not far away," he said, "there is another body, that of my servant, a youth from my own Province, whom I loved and whom I was educating. He was alive five minutes ago. He had just time to sob out the truth and his repentance."

"Tell me quickly, Pu-Yi, time presses."

"They caught him last night, so they must have been here then."

"Who caught him?"

"He never knew. They were masked, but there were two of them, and from his description we know very well who they were. Sir Thomas, they tortured him for a long time until he spoke, promising him freedom if he did so. His story was disjointed, gasped out with his dying breath, but I can put it together pretty well.

"They made him give an order by telephone from the upper City that, immediately, the staff were to leave here and descend to the ground and await further orders, all but Mulligan, who was to remain at his post until I came to him. This message was delivered in Chinese to the man at the telephone exchange, and the poor boy was forced to counterfeit my voice. He was blindfolded immediately afterwards, but he heard a man speaking, and he said he could not have told the voice from that of Mr. Morse."

In a flash I saw the whole thing, in its devilish ingenuity, its fiendish completeness.

"Then we are absolutely alone, you, I, Mr. Rolston, Mr. Morse and his daughter?"

"And her maid," he answered quietly.

"At the mercy of – "

"That we have yet to prove. We must throw all emotion, all fear aside. That's what we have to do now. It's diamond cut diamond. There's one problem in my mind, and one only."

"What's that, quick!"

"I daresay that in an hour I could get down to the ground. Among the intricate steel-work of this tower there's a tiny circular staircase of open lattice-work, sufficient for the passage of one person only, and even here, every three or four hundred feet the way is barred by locked gates, though I have a master key to all of them. Shall I make the attempt, and risk crashing off into space – for it is a mere steeplejack's way – and summon assistance, which may well be another hour in arriving, for the tower cables have been scientifically cut and no one but an electrician could repair them? Or shall I rush with you to defend the Palace?"

"You leave the decision to me?"

"It is in your hands, Prince."

"Then, old chap, tumble down this accursed tower, hell for leather, and rouse the pack. If I and Morse and Bill Rolston cannot account for these cowardly assassins, then one more man won't make any difference."

So I said, so I thought. I had no idea into what peril I was sending him, though I have sometimes wondered if he knew. He took my hand, kissed it, and beckoning me, we hurried through the silent under City towards the lift.

"You go up, Sir Thomas," he said, "and exercise the utmost care. Have your pistol ready. The mist is as thick as ever, which is in your favor. You can find your way now to the Palace, I am sure."

"And you?"

"I go off here," he said, pointing with his left arm down a long vista to where, under a square arch, there was nothing to be seen at all but swaying yellow-white. "One opens the gate in the railing and drops on to the circular stairs," he said, "which cling to the outside of the steel-work all the way down like a little train of ivy."

"Au revoir, be as quick as you can."

"Good-by," and I jumped into the elevator.

Some two minutes afterwards, when I was creeping through the wool with my pistol in my hand, alert for the slightest sound around me, I heard the sharp crack of a rifle. It came from behind me. There was a perceptible interval and then another crack, followed, I could have sworn to it, by a thin wailing cry.

Then utter silence fell once more upon the white and muffled City.

As I ran I tried to steel myself, if that were as I suspected, the last dying cry of Pu-Yi, not to think about it. The immediate moment, the immediate future, these were everything.

All the extraordinary precautions had failed. The assassins were here! In what force? How had they come? – though that was useless to speculate on. Two things only remained. I must warn Morse if it was not already too late, must avenge him if it was. I resolutely put aside the thought of Juanita – of any personal feeling which might mar my judgment and unstring my nerves at this supreme and dreadful moment.

I found myself, somehow or other, at the entrance to the tunneled passage. Save for my own quick breathing there had not been a sound, and the horrible curtain of the fog was as thick as ever. Should I at once creep up to the Palace, or should I go back to the villa and find Rolston? It was a nice question and the decision had to be instantaneous. I decided that it would give me a tremendous advantage to have him with me, and besides that, he himself must be warned of the terror that lurked in the darkness of the cloud.

I arrived without any mishap, pushed open the door and was crossing the dark hall when my foot caught in some obstruction and I fell headlong. There was no time to cry out, had I been startled enough to do so, before something leapt upon my back with a soft yet heavy thud. A hand slipped over my mouth and the round barrel of a pistol was pressed into my neck.

I lay helpless, thinking that it was all over, when the weight lifted, the pistol was snatched away and I was hauled to my feet to discover – Rolston.

"Not a word," he whispered. "I set a trap in the hall, Sir Thomas. Thank God you are alive!"

"Thank God you are too. Bill, they've strangled Mulligan, killed another Chinese by torture and I am very much afraid have shot Pu-Yi as he was trying to get down to earth to summon help.

"Every single member of the staff is down in the Park with orders to stay there – false orders. The lifts are all put out of action beyond possibility of being repaired for several hours. That's how things stand. Now we must get to the Palace as quickly as we possibly can. God knows what has happened or may be happening there."

"This way, quick!" he said, when he had listened to me with strained attention.

He took my arm, hurried me into the back part of the house, opened a door with a key and we entered a bedroom which I had not before seen. The windows were shuttered and curtained but the electric light – which never failed either my villa or the Palace during the whole of those terrible hours – made every detail clear. Upon the bed, lying as if asleep, was Juanita. Leaning over her was a tall, elderly, hard-featured French woman with a typical Norman face.

I staggered back into Bill Rolston's arms.

"Good God!" I cried, and then, "She's not dead, tell me she's not dead!"

Marie, the French maid, turned.

"She's perfectly well, M'sieu, only she's had a fainting fit and I've given her something to keep her quiet."

She spoke in French.

"Then how do you come here, what's happened?"

"At some time in the night, M'sieu, I think it must have been between two and three, the warning bell, which is always attached to my bed, began to ring. I knew exactly what to do. It was part of Mr. Morse's precautions, in which he had drilled us. When that bell rang, at whatever time of day or night, I was to wake M'selle instantly, dress her without a second's delay, and bring her out of the Palace by a secret way.

"I did so, and arrived in this room, where M'selle fainted. The door was locked from the outside, and as I have strict orders never to exceed my instructions by a hair's breadth, I have been waiting.

"Not very long ago M'sieu here" – she pointed to Rolston – "hearing some noise, unlocked the door and came in. To him I told what had happened."

"Thank God," I said aloud, "that she's safe," and in my heart I paid a tribute to the minutely detailed genius of Gideon Morse, who had at least foiled the panthers on his track in one, and the greatest particular.

"Very well then. Now we must leave you here while we hurry to the Palace to try and learn what has happened, and do what we can. You will not be afraid?"

"No, M'sieu," she replied simply. "There's an angel with us," and she crossed herself devoutly. "And, moreover," from somewhere about her waist she withdrew a long, keen knife, "I know what to do with this, M'sieu, in the last resort."

I went to the bed, I looked down at Juanita and kissed her gently on the forehead.

"Now then, Bill, come along," I said.

Bill grinned.

"By the private way," he said, pointing to the French woman, who was removing a heavy Turkish rug which lay in front of the fireplace. There was a click, and a portion of the floor fell down, disclosing some steps, padded with felt.

"This way, M'sieu," she whispered, "the passage is lit, but here's a torch if you should need it, and here is the book."

She handed me a little leather-bound book about the size of a railway ticket.

"What's this?"

"Instructions in English and Chinese in regard to the secret room at the other end. They are few and simple, but Mr. Morse had them printed so that there could be no mistake if ever it became necessary to use the place and its machinery."

"He thinks of everything," said Bill, as we crept down into a fairly wide passage, and the trap-door above rose once more into its place.

The passage was fully a hundred and thirty or forty yards long and straight as an arrow. As we approached the end, which I saw to be hidden by a heavy curtain, I thought of the little leather covered book. Motioning Rolston to stop I opened it and read the English portion. There were about five or six pages, with one or two simple diagrams, and I blessed the journalistic training that enabled me to see the purport of the whole thing in a minute, though I gasped once more at the fertile ingenuity of Gideon Morse. Gently putting aside the heavy curtain, we entered a room of some size. The floor was heavily carpeted. Around two of the walls were couches piled with blankets. Upon shelves above were piles of stores – I saw boxes of biscuits, tins of condensed milk and many bottles of wine. The place was quite fourteen feet high and at one end four posts came down from the ceiling to the floor. They were grooved and the grooves were lined with steel which was cogged to receive a toothed wheel. Between the four posts, dropping some two feet from the ceiling, was what looked like the lower part of a large cistern or tank. This apparatus extended along the whole far end of the room, which was not square but square-oblong in shape. Immediately opposite to where we entered was an arrangement of levers, like the levers in a railway signal-box, though smaller; above these, sprouting out of the wall, were half a dozen vulcanite mouthpieces like black trumpets. Above each one was a little ivory label.

"What does it all mean?" Bill whispered.

I held up my hand for silence, looking round the place, referring once or twice to the little book, and making absolutely sure. As I was doing so there was a sudden "pop," followed by the unmistakable gurgle of champagne into a glass.

It was the most uncanny thing I have ever heard, for it might have happened at my elbow. Had it not been that a tiny electric signal-bulb no bigger than a sixpence glowed out over one of the mouthpieces, I should have been utterly unnerved. This mouthpiece was labeled "Mr. Morse's study."

"The dictograph," I whispered to Rolston, and he pressed my arm to show he understood.

I think I would have given a thousand pounds myself for some champagne just then. We stood holding each other, frozen into an ecstasy of listening. I almost thought that one of Bill's remarkable ears was elongating itself until it coiled sinuously towards the wall, but this, no doubt, was illusion.

There came a voice, an urbane, and cultured voice, well modulated and serene.

It was all that, but as I heard it my blood seemed to turn to red currant jelly and to circulate no more in my veins. If there was ever a voice which was informed by some unnamable quality which came straight from the red pit of hell, we heard that voice then. Hearing it, I knew for the first time the meaning of those words: The worm that dies not and the fire that is not quenched.

"Whoever thought, Gideon Morse, that I should be breakfasting with you to-day! To tell the truth I didn't myself. But as you know, I have always been a great gambler and now, at the end of all the games of chance that we have played together, I have turned up the final ace."

Another voice – Heaven! it was Morse himself who answered. His voice seemed almost amused. It was like coming out of a pitch dark room into summer sunlight to hear it after that other.

"Mark Antony Midwinter, you speak of triumph, but you were never nearer your ultimate end than you are at this moment" – I could have sworn I heard his dry chuckle and I moved nearer to the wall.

"This cold pheasant is quite excellent. What is the use of trying to bluff me? Your end has come and you know it. It isn't going to be a pleasant end, I expect you guess that. We have tossed the dice for many years, you and I. You've won over and over again. I had become an outcast on the face of the earth, until Fate made me the agent of a great vengeance."

This time Morse laughed outright.

"You offal-eating jackal!" he said. "Finish your stolen meal and get to work. You, the agent of a great vengeance! when not long ago you slunk into my London hotel and offered to sell your employers. I understand," he went on in a curiously impersonal voice, "that you really are supposed to be descended from a high English family. Even when I had you tarred and feathered – do you remember that, Antony? – many years ago, I still believed in your descent, though I own I didn't give it much of a thought. Tell me, where exactly did the kitchen-maid come in?"

Following upon Morse's words we heard the sound of footsteps and the scraping of a chair.

A new person had come into the room and Midwinter had risen to meet him.

"Well?"

The reply came in a deep bass voice.

"Nothing is changed. There was one Chinaman, it must have been the librarian of whom that guy we put through it, spoke – he came sliding along and tried to get down by the cat's cradle outside the tower. I was leaning out of that balcony window above, commanding every approach, and I got him with my second shot."

"Did he fall all the way down? That might startle them below."

"No. He just crumpled up on the stairs, and after looking round, I've come back here. There's a little wind beginning to get up and I shouldn't wonder if in an hour or so this mist-blanket is all blown away."

"Half an hour is enough for what we have to do, Zorilla. Just go over to Mr. Morse there and see if his lashings are secure – and then we must think about getting off ourselves."

It was as though Bill and I could see exactly what was happening in the library – the heavy tread, an affirmative grunt, and then the smooth hellish voice resuming:

"You know you've got to die, Morse, and die painfully. Nothing can alter that, but I'll let you off part of your agonies if you tell me at once where your daughter is. It will only precipitate matters. We can easily find her as you must know."

"I don't like talking with you at all. You are both of you doomed beyond power of redemption. You have overcome some of my precautions, by what means I cannot tell. You've captured my person. You are about to wreak your disgusting vengeance on it. For Heaven's sake do so. You know nothing of this place you are in, or very little. Fools!" The voice rang out like a trumpet.

There was a murmured conference, the words of which we could not catch, then Midwinter said:

"We'll put you to the test a little, before Zorilla really begins – operating. Adjoining this apartment I see there is your most luxurious bathroom – the walls of onyx, the bath of solid silver. Well, we'll take you and put you in that bath and turn on the water. I'll stand over you, and with my hands on your shoulders, I'll plunge you an inch or two beneath the surface, till you are so nearly drowned that you taste all the bitterness of death. Then we'll have you up again and ask you a few questions. Perhaps you may have to go back into the bath a second time before Zorilla gets to the real work."

No words of mine can describe the malignancy of that voice, no words of mine can describe the shout of resolute, sardonic laughter which answered it.

Bill wanted to shout in answer, but I clapped my hand over his mouth just in time, and I could almost see the frowning faces of the two fiends as they advanced upon the bound man.