I wrote out a wire to Sandy, asking him to come up by the two-fifteen train and meet me at my flat.

'I have chosen my colleague,' I said.

'Billy Arbuthnot's boy? His father was at Harrow with me. I know the fellow - Harry used to bring him down to fish - tallish, with a lean, high-boned face and a pair of brown eyes like a pretty girl's. I know his record, too. There's a good deal about him in this office. He rode through Yemen, which no white man ever did before. The Arabs let him pass, for they thought him stark mad and argued that the hand of Allah was heavy enough on him without their efforts. He's blood-brother to every kind of Albanian bandit. Also he used to take a hand in Turkish politics, and got a huge reputation. Some Englishman was once complaining to old Mahmoud Shevkat about the scarcity of statesmen in Western Europe, and Mahmoud broke in with, "Have you not the Honourable Arbuthnot?" You say he's in your battalion. I was wondering what had become of him, for we tried to get hold of him here, but he had left no address. Ludovick Arbuthnot - yes, that's the man. Buried deep in the commissioned ranks of the New Army? Well, we'll get him out pretty quick!'

'I knew he had knocked about the East, but I didn't know he was that kind of swell. Sandy's not the chap to buck about himself.'

'He wouldn't,' said Sir Walter. 'He had always a more than Oriental reticence. I've got another colleague for you, if you like him.'

He looked at his watch. 'You can get to the Savoy Grill Room in five minutes in a taxi-cab. Go in from the Strand, turn to your left, and you will see in the alcove on the right-hand side a table with one large American gentleman sitting at it. They know him there, so he will have the table to himself. I want you to go and sit down beside him. Say you come from me. His name is Mr John Scantlebury Blenkiron, now a citizen of Boston, Mass., but born and raised in Indiana. Put this envelope in your pocket, but don't read its contents till you have talked to him. I want you to form your own opinion about Mr Blenkiron.' I went out of the Foreign Office in as muddled a frame of mind as any diplomatist who ever left its portals. I was most desperately depressed. To begin with, I was in a complete funk. I had always thought I was about as brave as the average man, but there's courage and courage, and mine was certainly not the impassive kind. Stick me down in a trench and I could stand being shot at as well as most people, and my blood could get hot if it were given a chance. But I think I had too much imagination. I couldn't shake off the beastly forecasts that kept crowding my mind.

In about a fortnight, I calculated, I would be dead. Shot as a spy - a rotten sort of ending! At the moment I was quite safe, looking for a taxi in the middle of Whitehall, but the sweat broke on my forehead. I felt as I had felt in my adventure before the war. But this was far worse, for it was more cold-blooded and premeditated, and I didn't seem to have even a sporting chance. I watched the figures in khaki passing on the pavement, and thought what a nice safe prospect they had compared to mine. Yes, even if next week they were in the Hohenzollern, or the Hairpin trench at the Quarries, or that ugly angle at Hooge. I wondered why I had not been happier that morning before I got that infernal wire. Suddenly all the trivialities of English life seemed to me inexpressibly dear and terribly far away. I was very angry with Bullivant, till I remembered how fair he had been. My fate was my own choosing.

When I was hunting the Black Stone the interest of the problem had helped to keep me going. But now I could see no problem. My mind had nothing to work on but three words of gibberish on a sheet of paper and a mystery of which Sir Walter had been convinced, but to which he couldn't give a name. It was like the story I had read of Saint Teresa setting off at the age of ten with her small brother to convert the Moors. I sat huddled in the taxi with my chin on my breast, wishing that I had lost a leg at Loos and been comfortably tucked away for the rest of the war.

Sure enough I found my man in the Grill Room. There he was, feeding solemnly, with a napkin tucked under his chin. He was a big fellow with a fat, sallow, clean-shaven face. I disregarded the hovering waiter and pulled up a chair beside the American at the little table. He turned on me a pair of full sleepy eyes, like a ruminating ox.

'Mr Blenkiron?' I asked.

'You have my name, Sir,' he said. 'Mr John Scantlebury Blenkiron. I would wish you good morning if I saw anything good in this darned British weather.'

'I come from Sir Walter Bullivant,' I said, speaking low.

'So?' said he. 'Sir Walter is a very good friend of mine. Pleased to meet you, Mr - or I guess it's Colonel -'

'Hannay,' I said; 'Major Hannay.' I was wondering what this sleepy Yankee could do to help me.

'Allow me to offer you luncheon, Major. Here, waiter, bring the carte. I regret that I cannot join you in sampling the efforts of the management of this ho-tel. I suffer, Sir, from dyspepsia - duo-denal dyspepsia. It gets me two hours after a meal and gives me hell just below the breast-bone. So I am obliged to adopt a diet. My nourishment is fish, Sir, and boiled milk and a little dry toast. It's a melancholy descent from the days when I could do justice to a lunch at Sherry's and sup off oyster-crabs and devilled bones.' He sighed from the depths of his capacious frame.

I ordered an omelette and a chop, and took another look at him. The large eyes seemed to be gazing steadily at me without seeing me. They were as vacant as an abstracted child's; but I had an uncomfortable feeling that they saw more than mine.

'You have been fighting, Major? The Battle of Loos? Well, I guess that must have been some battle. We in America respect the fighting of the British soldier, but we don't quite catch on to the de-vices of the British Generals. We opine that there is more bellicosity than science among your highbrows. That is so? My father fought at Chattanooga, but these eyes have seen nothing gorier than a Presidential election. Say, is there any way I could be let into a scene of real bloodshed?'

His serious tone made me laugh. 'There are plenty of your countrymen in the present show,' I said. 'The French Foreign Legion is full of young Americans, and so is our Army Service Corps. Half the chauffeurs you strike in France seem to come from the States.'

He sighed. 'I did think of some belligerent stunt a year back. But I reflected that the good God had not given John S. Blenkiron the kind of martial figure that would do credit to the tented field. Also I recollected that we Americans were nootrals - benevolent nootrals - and that it did not become me to be butting into the struggles of the effete monarchies of Europe. So I stopped at home. It was a big renunciation, Major, for I was lying sick during the Philippines business, and I have never seen the lawless passions of men let loose on a battlefield. And, as a stoodent of humanity, I hankered for the experience.'

'What have you been doing?' I asked. The calm gentleman had begun to interest me. 'Waal,' he said, 'I just waited. The Lord has blessed me with money to burn, so I didn't need to go scrambling like a wild cat for war con tracts. But I reckoned I would get let into the game somehow, and I was. Being a nootral, I was in an advantageous position to take a hand. I had a pretty hectic time for a while, and then I reckoned I would leave God's country and see what was doing in Europe. I have counted myself out of the bloodshed business, but, as your poet sings, peace has its victories not less renowned than war, and I reckon that means that a nootral can have a share in a scrap as well as a belligerent.'

'That's the best kind of neutrality I've ever heard of,' I said.

'It's the right kind,' he replied solemnly. 'Say, Major, what are your lot fighting for? For your own skins and your Empire and the peace of Europe. Waal, those ideals don't concern us one cent. We're not Europeans, and there aren't any German trenches on Long Island yet. You've made the ring in Europe, and if we came butting in it wouldn't be the rules of the game. You wouldn't welcome us, and I guess you'd be right. We're that delicate-minded we can't interfere and that was what my friend, President Wilson, meant when he opined that America was too proud to fight. So we're nootrals. But likewise we're benevolent nootrals. As I follow events, there's a skunk been let loose in the world, and the odour of it is going to make life none too sweet till it is cleared away. It wasn't us that stirred up that skunk, but we've got to take a hand in disinfecting the planet. See? We can't fight, but, by God! some of us are going to sweat blood to sweep the mess up. Officially we do nothing except give off Notes like a leaky boiler gives off steam. But as individooal citizens we're in it up to the neck. So, in the spirit of Jefferson Davis and Woodrow Wilson, I'm going to be the nootralist kind of nootral till Kaiser will be sorry he didn't declare war on America at the beginning.'

I was completely recovering my temper. This fellow was a perfect jewel, and his spirit put purpose into me.

'I guess you British were the same kind of nootral when your Admiral warned off the German fleet from interfering with Dewey in Manila Bay in '98.' Mr Blenkiron drank up the last drop of his boiled milk and lit a thin black cigar.

I leaned forward. 'Have you talked to Sir Walter?' I asked.

'I have talked to him, and he has given me to understand that there's a deal ahead which you're going to boss. There are no flies on that big man, and if he says it's good business then you can count me in.'

'You know that it's uncommonly dangerous?'

'I judged so. But it don't do to begin counting risks. I believe in an all-wise and beneficent Providence, but you have got to trust Him and give Him a chance. What's life anyhow? For me, it's living on a strict diet and having frequent pains in my stomach. It isn't such an almighty lot to give up, provided you get a good price in the deal. Besides, how big is the risk? About one o'clock in the morning, when you can't sleep, it will be the size of Mount Everest, but if you run out to meet it, it will be a hillock you can jump over. The grizzly looks very fierce when you're taking your ticket for the Rockies and wondering if you'll come back, but he's just an ordinary bear when you've got the sight of your rifle on him. I won't think about risks till I'm up to my neck in them and don't see the road out.'

I scribbled my address on a piece of paper and handed it to the stout philosopher. 'Come to dinner tonight at eight,' I said.

'I thank you, Major. A little fish, please, plain-boiled, and some hot milk. You will forgive me if I borrow your couch after the meal and spend the evening on my back. That is the advice of my noo doctor.'

I got a taxi and drove to my club. On the way I opened the envelope Sir Walter had given me. It contained a number of jottings, the dossier of Mr Blenkiron. He had done wonders for the Allies in the States. He had nosed out the Dumba plot, and had been instrumental in getting the portfolio of Dr Albert. Von Papen's spies had tried to murder him, after he had defeated an attempt to blow up one of the big gun factories. Sir Walter had written at the end: 'The best man we ever had. Better than Scudder. He would go through hell with a box of bismuth tablets and a pack of Patience cards.'

I went into the little back smoking-room, borrowed an atlas from the library, poked up the fire, and sat down to think. Mr Blenkiron had given me the fillip I needed. My mind was beginning to work now, and was running wide over the whole business. Not that I hoped to find anything by my cogitations. It wasn't thinking in an arm-chair that would solve the mystery. But I was getting a sort of grip on a plan of operations. And to my relief I had stopped thinking about the risks. Blenkiron had shamed me out of that. If a sedentary dyspeptic could show that kind of nerve, I wasn't going to be behind him.

I went back to my flat about five o'clock. My man Paddock had gone to the wars long ago, so I had shifted to one of the new blocks in Park Lane where they provide food and service. I kept the place on to have a home to go to when I got leave. It's a miserable business holidaying in an hotel.

Sandy was devouring tea-cakes with the serious resolution of a convalescent.

'Well, Dick, what's the news? Is it a brass hat or the boot?'

'Neither,' I said. 'But you and I are going to disappear from His Majesty's forces. Seconded for special service.'

'O my sainted aunt!' said Sandy. 'What is it? For Heaven's sake put me out of pain. Have we to tout deputations of suspicious neutrals over munition works or take the shivering journalist in a motor-car where he can imagine he sees a Boche?'

'The news will keep. But I can tell you this much. It's about as safe and easy as to go through the German lines with a walking-stick.'

'Come, that's not so dusty,' said Sandy, and began cheerfully on the muffins.

I must spare a moment to introduce Sandy to the reader, for he cannot be allowed to slip into this tale by a side-door. If you will consult the Peerage you will find that to Edward Cospatrick, fifteenth Baron Clanroyden, there was born in the year 1882, as his second son, Ludovick Gustavus Arbuthnot, commonly called the Honourable, etc. The said son was educated at Eton and New College, Oxford, was a captain in the Tweeddale Yeomanry, and served for some years as honorary attache at various embassies. The Peerage will stop short at this point, but that is by no means the end of the story. For the rest you must consult very different authorities. Lean brown men from the ends of the earth may be seen on the London pavements now and then in creased clothes, walking with the light outland step, slinking into clubs as if they could not remember whether or not they belonged to them. From them you may get news of Sandy. Better still, you will hear of him at little forgotten fishing ports where the Albanian mountains dip to the Adriatic. If you struck a Mecca pilgrimage the odds are you would meet a dozen of Sandy's friends in it. In shepherds' huts in the Caucasus you will find bits of his cast-off clothing, for he has a knack of shedding garments as he goes. In the caravanserais of Bokhara and Samarkand he is known, and there are shikaris in the Pamirs who still speak of him round their fires. If you were going to visit Petrograd or Rome or Cairo it would be no use asking him for introductions; if he gave them, they would lead you into strange haunts. But if Fate compelled you to go to Llasa or Yarkand or Seistan he could map out your road for you and pass the word to potent friends. We call ourselves insular, but the truth is that we are the only race on earth that can produce men capable of getting inside the skin of remote peoples. Perhaps the Scots are better than the English, but we're all a thousand per cent better than anybody else. Sandy was the wandering Scot carried to the pitch of genius. In old days he would have led a crusade or discovered a new road to the Indies. Today he merely roamed as the spirit moved him, till the war swept him up and dumped him down in my battalion.

I got out Sir Walter's half-sheet of note-paper. It was not the original - naturally he wanted to keep that - but it was a careful tracing. I took it that Harry Bullivant had not written down the words as a memo for his own use. People who follow his career have good memories. He must have written them in order that, if he perished and his body was found, his friends might get a clue. Wherefore, I argued, the words must be intelligible to somebody or other of our persuasion, and likewise they must be pretty well gibberish to any Turk or German that found them.

The first, 'Kasredin', I could make nothing of. I asked Sandy.

'You mean Nasr-ed-din,' he said, still munching crumpets.

'What's that?' I asked sharply. 'He's the General believed to be commanding against us in Mesopotamia. I remember him years ago in Aleppo. He talked bad French and drank the sweetest of sweet champagne.'

I looked closely at the paper. The 'K' was unmistakable.

'Kasredin is nothing. It means in Arabic the House of Faith, and might cover anything from Hagia Sofia to a suburban villa. What's your next puzzle, Dick? Have you entered for a prize competition in a weekly paper?'

'Cancer,' I read out.

'It is the Latin for a crab. Likewise it is the name of a painful disease. it is also a sign of the Zodiac.'

'V. I,' I read.

'There you have me. It sounds like the number of a motor-car. The police would find out for you. I call this rather a difficult competition. What's the prize?'

I passed him the paper. 'Who wrote it? It looks as if he had been in a hurry.'

'Harry Bullivant,' I said.

Sandy's face grew solemn. 'Old Harry. He was at my tutor's. The best fellow God ever made. I saw his name in the casualty list before Kut. ... Harry didn't do things without a purpose. What's the story of this paper?'

'Wait till after dinner,' I said. 'I'm going to change and have a bath. There's an American coming to dine, and he's part of the business.'

Mr Blenkiron arrived punctual to the minute in a fur coat like a Russian prince's. Now that I saw him on his feet I could judge him better. He had a fat face, but was not too plump in figure, and very muscular wrists showed below his shirt-cuffs. I fancied that, if the occasion called, he might be a good man with his hands.

Sandy and I ate a hearty meal, but the American picked at his boiled fish and sipped his milk a drop at a time. When the servant had cleared away, he was as good as his word and laid himself out on my sofa. I offered him a good cigar, but he preferred one of his own lean black abominations. Sandy stretched his length in an easy chair and lit his pipe. 'Now for your story, Dick,' he said.

I began, as Sir Walter had begun with me, by telling them about the puzzle in the Near East. I pitched a pretty good yarn, for I had been thinking a lot about it, and the mystery of the business had caught my fancy. Sandy got very keen.

'It is possible enough. Indeed, I've been expecting it, though I'm hanged if I can imagine what card the Germans have got up their sleeve. It might be any one of twenty things. Thirty years ago there was a bogus prophecy that played the devil in Yemen. Or it might be a flag such as Ali Wad Helu had, or a jewel like Solomon's necklace in Abyssinia. You never know what will start off a jehad! But I rather think it's a man.'

'Where could he get his purchase?' I asked.

'It's hard to say. If it were merely wild tribesmen like the Bedouin he might have got a reputation as a saint and miracle-worker. Or he might be a fellow that preached a pure religion, like the chap that founded the Senussi. But I'm inclined to think he must be something extra special if he can put a spell on the whole Moslem world. The Turk and the Persian wouldn't follow the ordinary new theology game. He must be of the Blood. Your Mahdis and Mullahs and Imams were nobodies, but they had only a local prestige. To capture all Islam - and I gather that is what we fear - the man must be of the Koreish, the tribe of the Prophet himself.'

'But how could any impostor prove that? For I suppose he's an impostor.'

'He would have to combine a lot of claims. His descent must be pretty good to begin with, and there are families, remember, that claim the Koreish blood. Then he'd have to be rather a wonder on his own account - saintly, eloquent, and that sort of thing. And I expect he'd have to show a sign, though what that could be I haven't a notion.'

'You know the East about as well as any living man. Do you think that kind of thing is possible?' I asked.

'Perfectly,' said Sandy, with a grave face.

'Well, there's the ground cleared to begin with. Then there's the evidence of pretty well every secret agent we possess. That all seems to prove the fact. But we have no details and no clues except that bit of paper.' I told them the story of it.

Sandy studied it with wrinkled brows. 'It beats me. But it may be the key for all that. A clue may be dumb in London and shout aloud at Baghdad.' 'That's just the point I was coming to. Sir Walter says this thing is about as important for our cause as big guns. He can't give me orders, but he offers the job of going out to find what the mischief is. Once he knows that, he says he can checkmate it. But it's got to be found out soon, for the mine may be sprung at any moment. I've taken on the job. Will you help?'

Sandy was studying the ceiling.

'I should add that it's about as safe as playing chuck-farthing at the Loos Cross-roads, the day you and I went in. And if we fail nobody can help us.'

'Oh, of course, of course,' said Sandy in an abstracted voice.

Mr Blenkiron, having finished his after-dinner recumbency, had sat up and pulled a small table towards him. From his pocket he had taken a pack of Patience cards and had begun to play the game called the Double Napoleon. He seemed to be oblivious of the conversation.

Suddenly I had a feeling that the whole affair was stark lunacy. Here were we three simpletons sitting in a London flat and projecting a mission into the enemy's citadel without an idea what we were to do or how we were to do it. And one of the three was looking at the ceiling, and whistling softly through his teeth, and another was playing Patience. The farce of the thing struck me so keenly that I laughed.

Sandy looked at me sharply.

'You feel like that? Same with me. It's idiocy, but all war is idiotic, and the most whole-hearted idiot is apt to win. We're to go on this mad trail wherever we think we can hit it. Well, I'm with you. But I don't mind admitting that I'm in a blue funk. I had got myself adjusted to this trench business and was quite happy. And now you have hoicked me out, and my feet are cold.'

'I don't believe you know what fear is,' I said.

'There you're wrong, Dick,' he said earnestly. 'Every man who isn't a maniac knows fear. I have done some daft things, but I never started on them without wishing they were over. Once I'm in the show I get easier, and by the time I'm coming out I'm sorry to leave it. But at the start my feet are icy.'

'Then I take it you're coming?'

'Rather,' he said. 'You didn't imagine I would go back on you?'

'And you, sir?' I addressed Blenkiron.

His game of Patience seemed to be coming out. He was completing eight little heaps of cards with a contented grunt. As I spoke, he raised his sleepy eyes and nodded.

'Why, yes,' he said. 'You gentlemen mustn't think that I haven't been following your most engrossing conversation. I guess I haven't missed a syllable. I find that a game of Patience stimulates the digestion after meals and conduces to quiet reflection. John S. Blenkiron is with you all the time.'

He shuffled the cards and dealt for a new game.

I don't think I ever expected a refusal, but this ready assent cheered me wonderfully. I couldn't have faced the thing alone.

'Well, that's settled. Now for ways and means. We three have got to put ourselves in the way of finding out Germany's secret, and we have to go where it is known. Somehow or other we have to reach Constantinople, and to beat the biggest area of country we must go by different roads. Sandy, my lad, you've got to get into Turkey. You're the only one of us that knows that engaging people. You can't get in by Europe very easily, so you must try Asia. What about the coast of Asia Minor?'

'It could be done,' he said. 'You'd better leave that entirely to me. I'll find out the best way. I suppose the Foreign Office will help me to get to the jumping-off place?'

'Remember,' I said, 'it's no good getting too far east. The secret, so far as concerns us, is still west of Constantinople.'

'I see that. I'll blow in on the Bosporus by a short tack.'

'For you, Mr Blenkiron, I would suggest a straight journey. You're an American, and can travel through Germany direct. But I wonder how far your activities in New York will allow you to pass as a neutral?'

'I have considered that, Sir,' he said. 'I have given some thought to the pecooliar psychology of the great German nation. As I read them they're as cunning as cats, and if you play the feline game they will outwit you every time. Yes, Sir, they are no slouches at sleuth- work. If I were to buy a pair of false whiskers and dye my hair and dress like a Baptist parson and go into Germany on the peace racket, I guess they'd be on my trail like a knife, and I should be shot as a spy inside of a week or doing solitary in the Moabite prison. But they lack the larger vision. They can be bluffed, Sir. With your approval I shall visit the Fatherland as John S. Blenkiron, once a thorn in the side of their brightest boys on the other side. But it will be a different John S. I reckon he will have experienced a change of heart. He will have come to appreciate the great, pure, noble soul of Germany, and he will be sorrowing for his past like a converted gun-man at a camp meeting. He will be a victim of the meanness and perfidy of the British Government. I am going to have a first-class row with your Foreign Office about my passport, and I am going to speak harsh words about them up and down this metropolis. I am going to be shadowed by your sleuths at my port of embarkation, and I guess I shall run up hard against the British Le-gations in Scandinavia. By that time our Teutonic friends will have begun to wonder what has happened to John S., and to think that maybe they have been mistaken in that child. So, when I get to Germany they will be waiting for me with an open mind. Then I judge my conduct will surprise and encourage them. I will confide to them valuable secret information about British preparations, and I will show up the British lion as the meanest kind of cur. You may trust me to make a good impression. After that I'll move eastwards, to see the demolition of the British Empire in those parts. By the way, where is the rendezvous?'

'This is the 17th day of November. If we can't find out what we want in two months we may chuck the job. On the 17th of January we should forgather in Constantinople. Whoever gets there first waits for the others. If by that date we're not all present, it will be considered that the missing man has got into trouble and must be given up. If ever we get there we'll be coming from different points and in different characters, so we want a rendezvous where all kinds of odd folk assemble. Sandy, you know Constantinople. You fix the meeting-place.'

'I've already thought of that,' he said, and going to the writing- table he drew a little plan on a sheet of paper. 'That lane runs down from the Kurdish Bazaar in Galata to the ferry of Ratchik. Half- way down on the left-hand side is a cafe kept by a Greek called Kuprasso. Behind the cafe is a garden, surrounded by high walls which were parts of the old Byzantine Theatre. At the end of the garden is a shanty called the Garden-house of Suliman the Red. It has been in its time a dancing-hall and a gambling hell and God knows what else. It's not a place for respectable people, but the ends of the earth converge there and no questions are asked. That's the best spot I can think of for a meeting-place.'

The kettle was simmering by the fire, the night was raw, and it seemed the hour for whisky-punch. I made a brew for Sandy and myself and boiled some milk for Blenkiron.

'What about language?' I asked. 'You're all right, Sandy?'

'I know German fairly well; and I can pass anywhere as a Turk. The first will do for eavesdropping and the second for ordinary business.'

'And you?' I asked Blenkiron.

'I was left out at Pentecost,' he said. 'I regret to confess I have no gift of tongues. But the part I have chosen for myself don't require the polyglot. Never forget I'm plain John S. Blenkiron, a citizen of the great American Republic.'

'You haven't told us your own line, Dick,' Sandy said.

'I am going to the Bosporus through Germany, and, not being a neutral, it won't be a very cushioned journey.'

Sandy looked grave.

'That sounds pretty desperate. Is your German good enough?'

'Pretty fair; quite good enough to pass as a native. But officially I shall not understand one word. I shall be a Boer from Western Cape Colony: one of Maritz's old lot who after a bit of trouble has got through Angola and reached Europe. I shall talk Dutch and nothing else. And, my hat! I shall be pretty bitter about the British. There's a powerful lot of good swear-words in the taal. I shall know all about Africa, and be panting to get another whack at the verdommt rooinek. With luck they may send me to the Uganda show or to Egypt, and I shall take care to go by Constantinople. If I'm to deal with the Mohammedan natives they're bound to show me what hand they hold. At least, that's the way I look at it.'

We filled our glasses - two of punch and one of milk - and drank to our next merry meeting. Then Sandy began to laugh, and I joined in. The sense of hopeless folly again descended on me. The best plans we could make were like a few buckets of water to ease the drought of the Sahara or the old lady who would have stopped the Atlantic with a broom. I thought with sympathy of little Saint Teresa.