'Well,' said the old man politely, 'are you rea.s.sured by your scrutiny, Sir?'

I couldn't find a word.

'I hope you'll find it consistent with your duty to drop this ridiculous business. I make no complaint, but you'll see how annoying it must be to respectable people.'

I shook my head.

'O Lord,' said the young man. 'This is a bit too thick!'

'Do you propose to march us off to the police station?' asked the plump one. 'That might be the best way out of it, but I suppose you won't be content with the local branch. I have the right to ask to see your warrant, but I don't wish to cast any aspersions upon you. You are only doing your duty. But you'll admit it's horribly awkward. What do you propose to do?'

There was nothing to do except to call in my men and have them arrested, or to confess my blunder and clear out. I felt mesmerized by the whole place, by the air of obvious innocence - not innocence merely, but frank honest bewilderment and concern in the three faces.

'Oh, Peter Pienaar,' I groaned inwardly, and for a moment I was very near d.a.m.ning myself for a fool and asking their pardon.

'Meantime I vote we have a game of bridge,' said the plump one. 'It will give Mr Hannay time to think over things, and you know we have been wanting a fourth player. Do you play, Sir?'

I accepted as if it had been an ordinary invitation at the club. The whole business had mesmerized me. We went into the smoking-room where a card-table was set out, and I was offered things to smoke and drink. I took my place at the table in a kind of dream. The window was open and the moon was flooding the cliffs and sea with a great tide of yellow light. There was moonshine, too, in my head. The three had recovered their composure, and were talking easily - just the kind of slangy talk you will hear in any golf club-house. I must have cut a rum figure, sitting there knitting my brows with my eyes wandering.

My partner was the young dark one. I play a fair hand at bridge, but I must have been rank bad that night. They saw that they had got me puzzled, and that put them more than ever at their ease. I kept looking at their faces, but they conveyed nothing to me. It was not that they looked different; they were different. I clung desperately to the words of Peter Pienaar.

Then something awoke me.

The old man laid down his hand to light a cigar. He didn't pick it up at once, but sat back for a moment in his chair, with his fingers tapping on his knees.

It was the movement I remembered when I had stood before him in the moorland farm, with the pistols of his servants behind me.

A little thing, lasting only a second, and the odds were a thousand to one that I might have had my eyes on my cards at the time and missed it. But I didn't, and, in a flash, the air seemed to clear. Some shadow lifted from my brain, and I was looking at the three men with full and absolute recognition.

The clock on the mantelpiece struck ten o'clock.

The three faces seemed to change before my eyes and reveal their secrets. The young one was the murderer. Now I saw cruelty and ruthlessness, where before I had only seen good-humour. His knife, I made certain, had skewered Scudder to the floor. His kind had put the bullet in Karolides.

The plump man's features seemed to dislimn, and form again, as I looked at them. He hadn't a face, only a hundred masks that he could a.s.sume when he pleased. That chap must have been a superb actor. Perhaps he had been Lord Alloa of the night before; perhaps not; it didn't matter. I wondered if he was the fellow who had first tracked Scudder, and left his card on him. Scudder had said he lisped, and I could imagine how the adoption of a lisp might add terror.

But the old man was the pick of the lot. He was sheer brain, icy, cool, calculating, as ruthless as a steam hammer. Now that my eyes were opened I wondered where I had seen the benevolence. His jaw was like chilled steel, and his eyes had the inhuman luminosity of a bird's. I went on playing, and every second a greater hate welled up in my heart. It almost choked me, and I couldn't answer when my partner spoke. Only a little longer could I endure their company.

'Whew! Bob! Look at the time,' said the old man. 'You'd better think about catching your train. Bob's got to go to town tonight,' he added, turning to me. The voice rang now as false as h.e.l.l. I looked at the clock, and it was nearly half-past ten.

'I am afraid he must put off his journey,' I said.

'Oh, d.a.m.n,' said the young man. 'I thought you had dropped that rot. I've simply got to go. You can have my address, and I'll give any security you like.'

'No,' I said, 'you must stay.'

At that I think they must have realized that the game was desperate. Their only chance had been to convince me that I was playing the fool, and that had failed. But the old man spoke again.

'I'll go bail for my nephew. That ought to content you, Mr Hannay.' Was it fancy, or did I detect some halt in the smoothness of that voice?

There must have been, for as I glanced at him, his eyelids fell in that hawk-like hood which fear had stamped on my memory.

I blew my whistle.

In an instant the lights were out. A pair of strong arms gripped me round the waist, covering the pockets in which a man might be expected to carry a pistol.

'SCHNELL, FRANZ,' cried a voice, 'DAS BOOT, DAS BOOT!' As it spoke I saw two of my fellows emerge on the moonlit lawn. The young dark man leapt for the window, was through it, and over the low fence before a hand could touch him. I grappled the old chap, and the room seemed to fill with figures. I saw the plump one collared, but my eyes were all for the out-of-doors, where Franz sped on over the road towards the railed entrance to the beach stairs. One man followed him, but he had no chance. The gate of the stairs locked behind the fugitive, and I stood staring, with my hands on the old boy's throat, for such a time as a man might take to descend those steps to the sea.

Suddenly my prisoner broke from me and flung himself on the wall. There was a click as if a lever had been pulled. Then came a low rumbling far, far below the ground, and through the window I saw a cloud of chalky dust pouring out of the shaft of the stairway.

Someone switched on the light.

The old man was looking at me with blazing eyes.

'He is safe,' he cried. 'You cannot follow in time ... He is gone ... He has triumphed ... DER SCHWARZE STEIN IST IN DER SIEGESKRONE.'

There was more in those eyes than any common triumph. They had been hooded like a bird of prey, and now they flamed with a hawk's pride. A white fanatic heat burned in them, and I realized for the first time the terrible thing I had been up against. This man was more than a spy; in his foul way he had been a patriot.

As the handcuffs clinked on his wrists I said my last word to him.

'I hope Franz will bear his triumph well. I ought to tell you that the ARIADNE for the last hour has been in our hands.'

Three weeks later, as all the world knows, we went to war. I joined the New Army the first week, and owing to my Matabele experience got a captain's commission straight off. But I had done my best service, I think, before I put on khaki.