"It's been a darned dull day," said Tommy, and yawned widely.

"Nearly tea time," said Tuppence and also yawned.

Business was not brisk in the International Detective Agency. The eagerly expected letter from the ham merchant had not arrived and bona fide cases were not forthcoming.

Albert, the office boy, entered with a sealed package which he laid on the table.

"The Mystery of the Sealed Packet," murmured Tommy. "Did it contain the fabulous pearls of the Russian Grand Duchess? Or was it an infernal machine destined to blow Blunt's Brilliant Detectives to pieces?"

"As a matter of fact," said Tuppence, tearing open the package, "it's my wedding present to Francis Haviland. Rather nice, isn't it?"

Tommy took a slender silver cigarette case from her outstretched hand, noted the inscription engraved in her own handwriting: Francis from Tuppence, opened and shut the case, and nodded approvingly.

"You do throw your money about, Tuppence," he remarked. "I'll have one like it, only in gold, for my birthday next month. Fancy wasting a thing like that on Francis Haviland, who always was and always will be one of the most perfect asses God ever made!"

"You forget I used to drive him about during the War, when he was a General. Ah! those were the good old days."

"They were," agreed Tommy. "Beautiful women used to come and squeeze my hand in Hospital, I remember. But I don't send them all wedding presents. I don't believe the bride will care much for this gift of yours, Tuppence."

"It's nice and slim for the pocket, isn't it?" said Tuppence disregarding his remarks.

Tommy slipped it into his own pocket.

"Just right," he said approvingly. ''Hullo, here is Albert with the afternoon post. Very possibly the Duchess of Pertheshire is commissioning us to find her prize Peke."

They sorted through the letters together. Suddenly Tommy gave vent to a prolonged whistle, and held up one of them in his hand.

"A blue letter with a Russian stamp on it. Do you remember what the Chief said? We were to look out for letters like that."

"How exciting," said Tuppence. "Something has happened at last. Open it and see if the contents are up to schedule. A ham merchant, wasn't it? Half a minute. We shall want some milk for tea. They forgot to leave it this morning. I'll send Albert out for it."

She returned from the outer office, after despatching Albert on his errand, to find Tommy holding the blue sheet of paper in his hand.

"As we thought, Tuppence," he remarked. "Almost word for word what the Chief said."

Tuppence took the letter from him and read it.

It was couched in careful stilted English, and purported to be from one Gregor Feodorsky who was anxious for news of his wife. The International Detective Agency was urged to spare no expense in doing their utmost to trace her. Feodorsky himself was unable to leave Russia at the moment owing to a crisis in the Pork trade.

"I wonder what it really means," said Tuppence thoughtfully, smoothing out the sheet on the table in front of her.

"Code of some kind, I suppose," said Tommy. "That's not our business. Our business is to hand it over to the Chief as soon as possible. Better just verify it by soaking off the stamp and seeing if the number 16 is underneath."

"All right," said Tuppence. "But I should think-"

She stopped dead, and Tommy, surprised by her sudden pause, looked up to see a man's burly figure blocking the doorway.

The intruder was a man of commanding presence, squareIy built, with a very round head and a powerful jaw. He might have been about forty-five years of age.

"I must beg your pardon," said the stranger, advancing into the room, hat in hand. "I found your outer office empty, and this door open, so I ventured to intrude. This is Blunt's International Detective Agency, is it not?"

"Certainly it is."

"And you are, perhaps, Mr. Blunt? Mr. Theodore Blunt?"

"I am Mr. Blunt. You wished to consult me? This is my secretary, Miss Robinson."

Tuppence inclined her head gracefully, but continued to scrutinise the stranger narrowly through her downcast eyelashes. She was wondering how long he had been standing in the doorway, and how much he had seen and heard. It did not escape her observation that even while he was talking to Tommy, his eyes kept coming back to the blue paper in her hand.

Tommy's voice, sharp with a warning note, recalled her to the needs of the moment.

"Miss Robinson, please, take notes. Now, sir, will you kindly state the matter on which you wish to have my advice?"

Tuppence reached for her pad and pencil.

The big man began in rather a harsh voice.

"My name is Bower. Dr. Charles Bower. I live in Hampstead where I have a practice. I have come to you, Mr. Blunt, because several rather strange occurrences have happened lately."

"Yes, Dr. Bower?"

"Twice in the course of the last week, I have been summoned by telephone to an urgent case-in each case to find that the summons has been a fake. The first time I thought a practical joke had been played upon me, but on my return the second time, I found that some of my private papers had been displaced and disarranged, and I now believe that the same thing had happened the first time. I made an exhaustive search and came to the conclusion that my whole desk had been thoroughly ransacked, and the various papers replaced hurriedly."

Dr. Bower paused, and gazed at Tommy.

"Well, Mr. Blunt?"

"Well, Dr. Bower," replied the young man smiling.

"What do you think of it, eh?"

"Well, first I should like the facts. What do you keep in your desk?"

"My private papers."

"Exactly. Now, what do those private papers consist of? What value are they to the common thief-or any particular person?"

"To the common thief I cannot see that they would have any value at all, but my notes on certain obscure alkaloids would be of interest to anyone possessed of technical knowledge on the subject. I have been making a study of such matters for the last few years. These alkaloids are deadly and virulent poisons, and are, in addition, almost untraceable. They yield no known reactions."

"The secret of them would be worth money, then?"

"To unscrupulous persons, yes."

"And you suspect-whom?"

The doctor shrugged his massive shoulders.

"As far as I can tell, the house was not entered forcibly from the outside. That seems to point to some member of my household, and yet I cannot believe-" He broke off abruptly, then began again, his face very grave.

"Mr. Blunt, I must place myself in your hands unreservedly. I dare not go to the police in the matter. Of my three servants I am almost entirely sure. They have served me long and faithfully. Still, one never knows. Then I have living with me my two nephews, Bertram and Henry. Henry is a good boy-a very good boy-he has never caused me any anxiety, an excellent hard-working young fellow. Bertram, I regret to say, is of quite a different character-wild, extravagant, and persistently idle."

"I see," said Tommy thoughtfully. "You suspect your nephew Bertram of being mixed up in this business. Now I don't agree with you. I suspect the good boy-Henry."

"But why?"

"Tradition. Precedent." Tommy waved his hand airily. "In my experience, the suspicious characters are always innocent-and vice versa, my dear sir. Yes, decidedly, I suspect Henry."

"Excuse me, Mr. Blunt," said Tuppence, interrupting in a deferential voice. "Did I understand Dr. Bower to say that these notes on-er-obscure alkaloids-are kept in the desk with the other papers?"

"They are kept in the desk, my dear young lady, but in a secret drawer, the position of which is known only to myself. Hence they have so far defied the search."

"And what exactly do you want me to do, Dr. Bower?" asked Tommy. "Do you anticipate that a further search will be made?"

"I do, Mr. Blunt. I have every reason to believe so. This afternoon, I received a telegram from a patient of mine whom I ordered to Bournemouth a few weeks ago. The telegram states that my patient is in a critical condition, and begs me to come down at once. Rendered suspicious by the events I have told you of, I myself despatched a telegram, prepaid, to the patient in question, and elicited the fact that he was in good health and had sent no summons to me of any kind. It occurred to me that if I pretended to have been taken in, and duly departed to Bournemouth, we should have a very good chance of finding the miscreants at work. They-or he -will doubtless wait until the household has retired to bed before commencing operations. I suggest that you should meet me outside my house at eleven o'clock this evening, and we will investigate the matter together."

"Hoping, in fact, to catch them in the act." Tommy drummed thoughtfully on the table with a paper knife. "Your plan seems to me an excellent one, Dr. Bower. I cannot see any hitch in it. Let me see, your address is-?"

"The Larches, Hangman's Lane-rather a lonely part, I am afraid. But we command magnificent views over the Heath."

"Quite so," said Tommy.

The visitor rose.

"Then I shall expect you to-night, Mr. Blunt. Outside The Larches at-shall we say, five minutes to eleven-to be on the safe side?"

"Certainly. Five minutes to eleven. Good afternoon, Dr. Bower."

Tommy rose, pressed the buzzer on his desk, and Albert appeared to show the client out. The doctor walked with a decided limp, but his powerful physique was evident in spite of it.

"An ugly customer to tackle," murmured Tommy to himself. "Well, Tuppence, old girl, what do you think of it?"

"I'll tell you in one word," said Tuppence. "Clubfoot!"

"What?"

"I said Clubfoot! My study of the Classics has not been in vain. Tommy, this thing's a plant. Obscure alkaloids indeed-I never heard a weaker story."

"Even I did not find it very convincing," admitted her husband.

"Did you see his eyes on the letter? Tommy, he's one of the gang. They've got wise to the fact that you're not the real Mr. Blunt, and they're out for our blood."