I sat in Paul Harley’s room. Luncheon was over, and although, as on the previous day, it had been a perfect repast, perfectly served, the sense of tension which I had experienced throughout the meal had made me horribly ill at ease.  
That shadow of which I have spoken elsewhere seemed to have become almost palpable. In vain I had ascribed it to a morbid imagination: persistently it lingered.
 
Madame de Stämer’s gaiety rang more false than ever. She twirled the rings upon her slender fingers and shot little enquiring glances all around the table. This spirit of unrest, from wherever it arose, had communicated itself to everybody. Madame’s several bon mots one and all were failures. She delivered them without conviction like an amateur repeating lines learned by heart. The Colonel was unusually silent, eating little but drinking much. There was something unreal, almost ghastly, about the whole affair; and when at last Madame de Stämer retired, bearing Val Beverley with her, I felt certain that the Colonel would make some communication to us. If ever knowledge of portentous evil were written upon a man’s face it was written upon his, as he sat there at the head of the table, staring straightly before him. However:
 
“Gentlemen,” he said, “if your enquiries here have led to no result of, shall I say, a tangible character, at least I feel sure that you must have realized one thing.”
 
Harley stared at him sternly.
 
“I have realized, Colonel Menendez,” he replied, “that something is pending.”
 
“Ah!” murmured the Colonel, and he clutched the edge of the table with his strong brown hands.
 
“But,” continued my friend, “I have realized something more. You have asked for my aid, and I am here. Now you have deliberately tied my hands.”
 
“What do you mean, sir?” asked the other, softly.
 
“I will speak plainly. I mean that you know more about the nature of this danger than you have ever communicated to me. Allow me to proceed, if you please, Colonel Menendez. For your delightful hospitality I thank you. As your guest I could be happy, but as a professional investigator whose services have been called upon under most unusual circumstances, I cannot be happy and I do not thank you.”
 
Their glances met. Both were angry, wilful, and self-confident. Following a few moments of silence:
 
“Perhaps, Mr. Harley,” said the Colonel, “you have something further to say?”
 
“I have this to say,” was the answer: “I esteem your friendship, but I fear I must return to town without delay.”
 
The Colonel’s jaws were clenched so tightly that I could see the muscles protruding. He was fighting an inward battle; then:
 
“What!” he said, “you would desert me?”
 
“I never deserted any man who sought my aid.”
 
“I have sought your aid.”
 
“Then accept it!” cried Harley. “This, or allow me to retire from the case. You ask me to find an enemy who threatens you, and you withhold every clue which could aid me in my search.”
 
“What clue have I withheld?”
 
Paul Harley stood up.
 
“It is useless to discuss the matter further, Colonel Menendez,” he said, coldly.
 
The Colonel rose also, and:
 
“Mr. Harley,” he replied, and his high voice was ill-controlled, “if I give you my word of honour that I dare not tell you more, and if, having done so, I beg of you to remain at least another night, can you refuse me?”
 
Harley stood at the end of the table watching him.
 
“Colonel Menendez,” he said, “this would appear to be a game in which my handicap rests on the fact that I do not know against whom I am pitted. Very well. You leave me no alternative but to reply that I will stay.”
 
“I thank you, Mr. Harley. As I fear I am far from well, dare I hope to be excused if I retire to my room for an hour’s rest?”
 
Harley and I bowed, and the Colonel, returning our salutations, walked slowly out, his bearing one of grace and dignity. So that memorable luncheon terminated, and now we found ourselves alone and faced with a problem which, from whatever point one viewed it, offered no single opening whereby one might hope to penetrate to the truth.
 
Paul Harley was pacing up and down the room in a state of such nervous irritability as I never remembered to have witnessed in him before.
 
I had just finished an account of my visit to the Guest House and of the indignity which had been put upon me, and:
 
“Conundrums! conundrums!” my friend exclaimed. “This quest of Bat Wing is like the quest of heaven, Knox. A hundred open doors in............