“Give me the whole story,” said Mr. Brinn, “right from the beginning.”  He looked up.  “Do you know what you have done to-night, Mr. Harley?”

Paul Harley shook his head.  Swiftly, like the touch of an icy finger, that warning note of danger had reached him again.

“I’ll tell you,” continued Brinn.  “You have opened the gates of hell!”

Not another word did he speak while Paul Harley, pacing slowly up and down before the hearth, gave him a plain account of the case, omitting all reference to his personal suspicions and to the measures which he had taken to confirm them.

He laid his cards upon the table deliberately.  Whether Sir Charles Abingdon had uttered the name of Nicol Brinn as that of one whose aid should be sought or as a warning, he had yet to learn.  And by this apparent frankness he hoped to achieve his object.  That the celebrated American was in any way concerned in the menace which had overhung Sir Charles he was not prepared to believe.  But he awaited with curiosity that explanation which Nicol Brinn must feel called upon to offer.

“You think he was murdered?” said Brinn in his high, toneless voice.

“I have formed no definite opinion.  What is your own?”

“I may not look it,” replied Brinn, “but at this present moment I am the most hopelessly puzzled and badly frightened man in London.”

“Frightened?” asked Harley, curiously.

“I said frightened, I also said puzzled; and I am far too puzzled to be able to express any opinion respecting the death of Sir Charles Abingdon.  When I tell you all I know of him you will wonder as much as I do, Mr. Harley, why my name should have been the last to pass his lips.”

He half turned in the big chair to face his visitor, who now was standing before the fireplace staring down at him.

“One day last month,” he resumed, “I got out of my car in a big hurry at the top of the Haymarket.  A fool on a motorcycle passed between the car and the sidewalk just as I stepped down, and I knew nothing further until I woke up in a drug store close by, feeling very dazed and with my coat in tatters and my left arm numbed from the elbow.  A man was standing watching me, and presently when I had pulled round he gave me his card.

“He was Sir Charles Abingdon, who had been passing at the time of the accident.  That was how I met him, and as there was nothing seriously wrong with me I saw him no more professionally.  But he dined with me a week later and I had lunch at his club about a fortnight ago.”

He looked up at Harley.  “On my solemn word of honour,” he said, “that’s all I know about Sir Charles Abingdon.”

Paul Harley returned the other’s fixed stare.  “I don’t doubt your assurance on the point, Mr. Brinn,” he acknowledged.  “I can well understand that you must be badly puzzled; but I would remind you of your statement that you were also frightened.  Why?”