"It's a crime. Fools - that's what we are - fools. Why don't we intern all these refugees?" Major Bletchley was well away.

"End of the story was I bought the place when it came i

nto the market," continued the Commander, not to be sidetracked from his pet story. "Come in and have a look round, Meadowes?"

"Thanks. I'd like to."

Commander Haydock was as full of zest as a boy as he did the honours of the establishment. He threw open the big safe in the dining room to show where the secret wireless had been found. Tommy was taken out to the garage and was shown where the big petrol tanks had been concealed, and finally, after a superficial glance at the two excellent bathrooms, the special lighting, and the various kitchen "gadgets," he was taken down the steep concreted path to the little cove beneath, whilst Commander Haydock told him all over again how extremely useful the whole layout would be to an enemy in wartime.

He was taken into the cave which gave the place its name, and Haydock pointed out enthusiastically how it could have been used.

Major Bletchley did not accompany the two men on their tour, but remained peacefully sipping his drink on the terrace. Tommy gathered that the Commander's spy hunt with its successful issue was that good gentleman's principal topic of conversation, and that his friends had heard it many times.

In fact, Major Bletchley said as much when they were walking down to Sans Souci a little later.

"Good fellow, Haydock," he said. "But he's, not content to let a good thing alone. We've heard all about that business again and again until we're sick of it. He's as proud of the whole bag of tricks up there as a cat of its kittens."

The simile was not too far-fetched, and Tommy assented with a smile.

The conversation then turning to Major Bletchley's own successful unmasking of a dishonest bearer in 1923, Tommy's attention was free to pursue its own inward line of thought punctuated by sympathetic "Not reallys?" - "You don't say so?" and "What an extraordinary business!" which was all Major Bletchley needed in the way of encouragement.

More than ever now, Tommy felt that when the dying Farquhar had mentioned Sans Souci he had been on the right track. Here, in this out of the world spot, preparations had been made a long time beforehand. The arrival of the German Hahn and his extensive installation showed clearly enough that this particular part of the coast had been selected for a rallying point, a focus of enemy activity.

That particular game had been defeated by the unexpected activity of the suspicious Commander Haydock. Round One had gone to Britain. But supposing that Smugglers' Rest had been only the first outpost of a complicated scheme of attack? Smugglers' Rest, that is to say, had represented sea communications. Its beach, inaccessible save for the path down from above, would lend itself admirably to the plan. But it was only a part of the whole.

Defeated on that part of the plan by Haydock, what had been the enemy's response? Might not he have fallen back upon the next best thing - that is to say, Sans Souci? The exposure of Hahn had come about four years ago. Tommy had an idea, from what Sheila Perenna had said, that it was very soon after that that Mrs Perenna had returned to England and bought Sans Souci. The next move in the game?

It would seem, therefore, that Leahampton was definitely an enemy center - that there were already installations and affiliations in the neighborhood.

His spirits rose. The depression engendered by the harmless and futile atmosphere of Sans Souci disappeared. Innocent as it seemed, that innocence was no more than skin deep. Behind that innocuous mask things were going on.

And the focus of it all, so far as Tommy could judge, was Mrs Perenna. The first thing to do was to know more about Mrs Perenna, to penetrate behind her apparently simple routine of running her boarding establishment. Her correspondence, her acquaintances, her social or war working activities - somewhere in all these must lie the essence of her real activities. If Mrs Perenna was the renowned woman agent, M, then it was she who controlled the whole of the Fifth Column activities in this country. Her identity would be known to few - only to those at the top. But communications she must have with her chiefs of staff, and it was those communications that he and Tuppence had got to tap.

At the right moment, as Tommy saw well enough, Smugglers' Rest could be seized and held - by a few stalwarts operating from Sans Souci. That moment was not yet, but it might be very near.

Once the German Army was established in control of the channel ports in France and Belgium, they could concentrate on the invasion and subjugation of Britain, and things were certainly going very badly in France at the moment.

Britain's Navy was all-powerful on the sea, so the attack must come by air and by internal treachery - and if the threads of internal treachery were in Mrs Perenna's keeping, there was no time to lose.

Major Bletchley's words chimed in with his thoughts:

"I saw, you know, that there was no time to lose. I got hold of Abdul, my sayce - good fellow, Abdul -"

The story droned on.

Tommy was thinking:

"Why Leahampton? Any reason? It's out of the main stream - bit of a backwater. Conservative, old-fashioned. All those points make it desirable. Is there anything else?"

There was a stretch of flat agricultural country behind it, running inland. A lot of pasture. Suitable, therefore, for the landing of troop-carrying airplanes or of parachute troops. But that was true of many other places. There was also a big chemical works where, it might be noted, Carl von Deinim was employed.

Carl von Deinim. How did he fit in? Only too well. He was not, as Grant had pointed out, the real head. A cog, only, in the machine. Liable to suspicion and internment at any moment. But in the meantime, he might have accomplished what had been his task. He had mentioned to Tuppence that he was working on decontamination problems and on the immunizing of certain gases. There were probabilities there - probabilities unpleasant to contemplate.

Carl, Tommy decided (a little reluctantly) was in it. A pity, because he rather liked the fellow. Well, he was working for his country - taking his life in his hands. Tommy had respect for such an adversary - down him by all means - a firing party was the end, but you knew that when you took on your job.

It was the people who betrayed their own land - from within - that really roused a slow vindictive passion in him. By God, he'd get them!

"- And that's how I got them!" The Major wound up his story triumphantly. "Pretty smart bit of work, eh?"

Unblushingly Tommy said:

"Most ingenious thing I've heard in my life, Major."

II

Mrs Blenkensop was reading a letter on thin foreign paper, stamped outside with the censor's mark.

"Dear Raymond," she murmured. "I was so happy about him out in Egypt, and now, it seems, there is a big change round. All very secret, of course, and he can't say anything - just that there really is a marvellous plan and that I'm to be ready for some big surprises soon. I'm glad to know where he's being sent, but I really don't see why -"

Bletchley grunted.

"Surely he's not allowed to tell you that?"

Tuppence gave a deprecating laugh and looked round the breakfast table as she folded up her precious letter.

"Oh! We have our methods," she said archly. "Dear Raymond knows that if only I know where he is or where he's going I don't worry quite so much. It's quite a simple way, too. Just a certain word, you know, and after it the initial letters of the next words spell out the place. Of course it makes rather a funny sentence sometimes - but Raymond is really most ingenious. I'm sure nobody would notice."

Little murmurs arose round the table. The moment was well chosen, everybody happened to be at the breakfast table together for once.

Bletchley, his face rather red, said:

"You'll excuse me, Mrs Blenkensop, but that's a damned foolish thing to do. Movements of troops and air squadrons are just what the Germans want to know."

"Oh, but I never tell anyone," cried Tuppence. "I'm very, very careful."

"All the same it's an unwise thing to do - and your boy will get into trouble over it some day."

"Oh, I do hope not. I'm his mother, you see. A mother ought to know."

"Indeed

and I think you're right," boomed out Mrs O'Rourke. "Wild horses wouldn't drag the information from you - we know that."

"Letters can be read," said Bletchley.

"I'm very careful never to leave letters lying about," said Tuppence with an air of outraged dignity. "I always keep them locked up."

Bletchley shook his head doubtfully.

III

It was a grey morning with the wind blowing coldly from the sea. Tuppence was alone at the far, end of the beach.