At eleven o'clock next morning a motor car drove up to Keldale House and an exceedingly affable and pleasing stranger delivered a note from Mr. Simon Rattar to Mr. James Bisset. Even without an introduction, Mr. Carrington would have been welcome, for though Mr. Bisset's sway over Keldale House was by this time almost despotic, he had begun to find that despotism has its lonely side, and to miss "the gentry." With an introduction, Mr. Carrington quickly discovered that Mr. Bisset and the mansion he supervised were alike entirely at his disposal.

The preliminary discussion on the sporting possibilities of the estate and the probability of its being let next season impressed Mr. Bisset very favourably indeed with his visitor; and then when the conversation had passed very naturally to the late tragedy in the house, he was still further delighted to find that Mr. Carrington not only shared his own detective enthusiasm, but was vastly interested in his views on this particular mystery.

"Come along here, sir," said he, "we can just have a look at the library and I'll explain to you the principles of the thing."

"I'd like to see the actual scene of the crime immensely!" cried Mr. Carrington eagerly. "You are sure that Lady Cromarty won't object?"

"Not her," said Bisset. "She's never in this part of the house now. She'll be none the wiser anyhow."

This argument seemed to assure Mr. Carrington completely, and they went along to the library.

"Now," began Bisset, "I'll just explain to you the haill situation. Here where I'm laying this sofie cushion was the corp. Here where I'm standing the now was the wee table, and yon's the table itself."

To the disquisition that followed, Mr. Carrington listened with the most intelligent air. Bisset had by this time evolved quite a number of new theories, but the one feature common to them all was the hypothesis that the murderer must have come in by the window and was certainly not an inmate of the household. His visitor said little till he had finished, and then he remarked:

"Well, Bisset, you don't seem to put much faith in the current theory, I see."

"Meaning that Sir Malcolm and Miss Farmond were concerned?" said Bisset indignantly. "That's just the ignorance of the uneducated masses, sir! The thing's physically impossible, as I've just been demonstrating!"

Carrington smiled and gently shook his head.

"I don't know much about these things," said he, "but I'm afraid I can't see the physical impossibility. It was very easy for any one in the house to come downstairs and open that door, and if Sir Reginald knew him, it would account for his silence and the absence of any kind of a struggle."

"But yon table and the windie being unfastened! And the mud I picked up myself—and the hearth brush!"

"They scarcely make it impossible," said Carrington.

"Well, sir," demanded the butler, "what's your own theory?"

Carrington said nothing for several minutes. He strolled up and down the room, looked at the table and the window, and at last asked:

"Do you remember quite distinctly what Sir Reginald looked like when you found him—the position of the body—condition of the clothes—and everything else?"

"I see him lying there every night o' my life, just as plain as I see you now!"

"The feet were towards the door, just as though he had been facing the door when he was struck down?"

"Aye, but then my view is the body was moved——"

He was interrupted by a curious performance on Mr. Carrington's part. His visitor was in fact stretching himself out on the floor on the spot where Sir Reginald was found.

"He lay like this?" he asked.

"Aye, practically just like that, sir."

"Now, Bisset," said the recumbent visitor, "just have a very good look at me and tell me if you notice any difference between me and the body of Sir Reginald."

Bisset looked for a few seconds and then exclaimed:

"Your clothes are no alike! The master's coat was kind of pulled up like about his shoulders and neck. Oh, and I mind now the tag at the back for hanging it up was broken and sticking out."

Carrington sprang to his feet with a gleam in his eye.

"The tag was not broken before he put on the coat?"

"It certainly was not that! But what's your deduction, sir?"

Carrington smiled at him.

"What do you think yourself, Bisset? You saw how I threw myself down quite carelessly and yet my coat wasn't pulled up like that."

"God, sir!" cried the butler. "You mean the corp had been pulled along the floor by the shoulders!"

Carrington nodded.

"Then he had been killed near the windie!"

"Not too fast, not too fast!" smiled Carrington. "Your own first statement which I happened to read in a back number of the newspaper the other day said that the windows were all fastened when Sir Reginald came into the room."

"Ah, but I've been altering my opinion on that point, sir."

Carrington shook his head.

"I'm afraid because a fastened window doesn't suit your theory."

"But the master might have opened it to him, thinking it was some one he knew."

"Sounds improbable," said Carrington thoughtfully.

"But not just absolutely impossible."

"No," said Carrington, still very thoughtfully, "not impossible."

"Sir Reginald might never have seen it was a stranger till the man was fairly inside."

Carrington smiled and shook his head.

"Thin, Bisset; very thin. Why need the man have been a stranger at all?"

Bisset's face fell.

"But surely you're not believing yon story that it was Sir Malcolm and Miss Farmond after a'?"

His visitor stood absolutely silent for a full minute. Then he seemed suddenly to banish the line of thought he was following.

"Is it quite certain that those two are engaged?" he asked.

Bisset's face showed his surprise at the question.

"They all say so," said he.

"Have either of them admitted it?"

"No, sir."

"Why don't they acknowledge it now and get married?"

"They say it's because they daurna for fear of the scandal."

"'They' say again!" commented Carrington. "But, look here, Bisset, you have been in the house all the time. Did you think they were engaged?"

"Honestly, sir, I did not. There's nae doubt Sir Malcolm was sweet on the young lady, but deil a sign of sweetness on him did I ever see in her!"

"Do they correspond now?"

Bisset shook his head.

"Hardly at a'. But of course folks just say they are feared to now."

"Has anybody asked either of them if they are—or ever were—engaged?"

"No, sir. But if they denied it now, folks would just say the same thing."

"Yes. I see—naturally. Lady Cromarty believes it and is keeping Miss Farmond under her eye, the gossips tell me. Is that so?"

"Oh, that's true right enough, sir."

"Who told Lady Cromarty?"

"That I do not know, sir."

Again the visitor seemed to be thinking, and again to cast his thoughts aside and take up a new aspect of the case.

"Supposing," he suggested, "we were to draw the curtains and light these candles for a few minutes? It might help us to realise the whole thing."

This suggestion pleased Mr. Bisset greatly and in a minute or two the candles were lit and the curtains drawn.

"Put the table where it stood," said Carrington. "Now which was Sir Reginald's chair? This?"

He sat in it and looked slowly round the darkened, candle-lit library.

"Now," said he, "suppose I was Sir Reginald, and there came a tap at that window, what would I do?"

"If you were the master, sir, you'd go straight to the windie to see who it was."

"I wouldn't get in a funk and ring the bell?"

"No fears!" said Bisset confidently.

"And any one who knew Sir Reginald at all well could count on his not giving the alarm then if they tapped at the window?"

"They could that."

Carrington looked attentively towards the window.

"Those curtains hang close against the window, I see," he observed. "A very slight gap in them would enable any one to get a good view of the room, if the blinds were not down. Were the blinds down that night?"

Bisset slapped his knee.

"The middle blind wasn't working!" he cried. "What a fool I've been not to think on the extraordinar' significance of that fac'! My, the deductions to be drawn! You've made it quite clear now, sir. The man tappit at that windie——"

"Steady, steady!" said Carrington, smiling and yet seriously. "Don't you go announcing that theory! If there's anything in it—mum's the word! But mind you, Bisset, it's only a bare possibility. There's no good evidence against the door theory yet."

"Not the table being cowpit and the body moved?"

"They might be explained."

He was thoughtful for a moment and then said deliberately:

"I want—I mean you want certain evidence to exclude the door theory. Without that, the window theory remains a guess. Sir Malcolm is in London, I understand?"

"Yes, sir."

"Likely to be coming north soon?"

"No word of it, sir."

Mr. Carrington reflected for a moment and then rose and went towards the window.

"We can draw back the curtains now," said he.

He drew them as he spoke and on the instant stepped involuntarily back and down went the small table. Miss Cicely Farmond was standing just outside, evidently arrested by the drawn curtains. Her eyes opened very wide indeed at the sight of Mr. Carrington suddenly revealed. Her lips parted for an instant as though she would cry out, and then she hurried away.

Mr. Carrington seemed more upset by this incident than one would expect from such a composed, easy-going young man.

"What will they think of me!" he exclaimed. "You must be sure to tell Miss Farmond—and Lady Cromarty too if she hears of this—that I came solely to enquire about the shootings and not to poke my nose into their library! Make that very explicit, Bisset."

Even though assured by Bisset that the young lady was the most amiable person imaginable, he was continuing to lay stress on the point when his attention was abruptly diverted by the sight of another lady in deep black walking slowly away from the house.

"Is that Lady Cromarty?" he asked, and no sooner had Bisset said "yes" than the window was up and Mr. Carrington stepping out of it.

"I really must explain and apologise to her ladyship," said he.

"Her ladyship will never know——!" began Bisset, but the surprising visitor was already hastening after the mourning figure. Had the worthy man been able to hear the conversation which ensued he would have been more surprised still.

"Lady Cromarty, I believe?" said the stranger in a deferential voice.

She turned quickly, and her eyes searched him with that hard glance they wore always nowadays.

"Yes, I am Lady Cromarty," she said.

"Pardon me for disturbing you," said he. "It is a mere brief matter of business. I represent an insurance company to which Sir Malcolm Cromarty has made certain proposals. We are not perfectly satisfied with his statements, and from other sources learn that he is engaged to be married. I have come simply to ascertain whether that is the case."

Lady Cromarty was (as Mr. Carrington had shrewdly divined) no better versed in the intricate matter of insurance than the majority of her sex, and evidently perceived nothing very unusual in this enquiry. It may be added in her excuse that the manner in which it was put by the representative of the company was a perfect example of how a business man should address a lady.

"It is the case," said she.

"May I ask your ladyship's authority—in strict confidence of course?" enquired the representative firmly, but very courteously.

"I learned it from my own man of business," said she.

"Thank you," said the insurance representative. "I beg that your ladyship will say nothing of my call, and I shall undertake not to mention the source of my information," and with an adequate bow he returned to the house.

Before disappearing through her library window, Mr. Carrington saw that her ladyship's back was turned, and he then gave this candid, if somewhat sketchy, account of his interview to her butler.

"It suddenly struck me," said he, "that Lady Cromarty might think it somewhat unseemly of me to come enquiring about shooting so soon after her bereavement; so I gave her a somewhat different explanation. She is not likely to make any further enquiries about me and so you need say nothing about my visit."

He was careful however to impress on his friend Mr. Bisset that he actually had come from purely sporting motives. In fact he professed some anxiety to get in touch with Sir Malcolm on the subject, even though assured that the young baronet had nothing to do with the shootings.

"Ah, but it will gratify him, Bisset," said he, "and I think it is the nice thing to do. Could you give me his London address?"

He jotted this down in his pocket book, and then as he was leaving he said confidentially:

"You tell me that you think Sir Malcolm is interested in Miss Farmond, though she seemed not so keen on him?"

"That was the way of it to my thinking," said Bisset. "And what deduction would you draw from that, sir?"

"I should deduce," said this sympathetic and intelligent visitor, "the probable appearance of certain evidence bearing on our theories, Bisset."

Mr. Bisset thought he had seldom met a pleasanter gentleman or a more helpful assistant.