“Then—­I received what I may term a warning.  My position is a peculiar one—­ a peculiar one.  My daughter, too, saw this prowling person, over by the Roman castrum, and described him as a yellow man.  It was the incident in the train following closely upon this other, which led me to speak to the police, little as I desired to—­er—­court publicity.”

Nayland Smith walked to a window, and looked out across the sloping lawn to where the shadows of the shrubbery lay.  A dog was howling dismally somewhere.

“Your defenses are not impregnable, after all, then?” he jerked.  “On our way up this evening Mr. Denby was telling us about the death of his collie a few nights ago.”

The clergyman’s face clouded.

“That, certainly, was alarming,” he confessed.

“I had been in London for a few days, and during my absence Vernon came down, bringing the dog with him.  On the night of his arrival it ran, barking, into the shrubbery yonder, and did not come out.  He went to look for it with a lantern, and found it lying among the bushes, quite dead.  The poor creature had been dreadfully beaten about the head.”

“The gates were locked,” Denby interrupted, “and no one could have got out of the grounds without a ladder and someone to assist him.  But there was so sign of a living thing about.  Edwards and I searched every corner.”

“How long has that other dog taken to howling?” inquired Smith.

“Only since Rex’s death,” said Denby quickly.

“It is my mastiff,” explained the clergyman, “and he is confined in the yard.  He is never allowed on this side of the house.”

Nayland Smith wandered aimlessly about the library.

“I am sorry to have to press you, Mr. Eltham,” he said, “but what was the nature of the warning to which you referred, and from whom did it come?”

Mr. Eltham hesitated for a long time.

“I have been so unfortunate,” he said at last, “in my previous efforts, that I feel assured of your hostile criticism when I tell you that I am contemplating an immediate return to Ho-Nan!”

Smith jumped round upon him as though moved by a spring.

“Then you are going back to Nan-Yang?” he cried. 
“Now I understand!  Why have you not told me before? 
That is the key for which I have vainly been seeking. 
Your troubles date from the time of your decision to return?”

“Yes, I must admit it,” confessed the clergyman diffidently.

“And your warning came from China?”

“It did.”

“From a Chinaman?”

“From the Mandarin, Yen-Sun-Yat.”

“Yen-Sun-Yat!  My good sir!  He warned you to abandon your visit?  And you reject his advice?  Listen to me.”  Smith was intensely excited now, his eyes bright, his lean figure curiously strung up, alert.  “The Mandarin Yen-Sun-Yat is one of the seven!”

“I do not follow you, Mr. Smith.”