When the invitation came from my old friend Hilton to spend a week "roughing it" with him in Warwickshire I accepted with alacrity. If ever a man needed a holiday I was that man. Nervous breakdown threatened me at any moment; the ghastly experience at the Gate House together with Carneta's grief-stricken face when I had parted from her were obsessing memories which I sought in vain to shake off.  
A brief wire had contained the welcome invitation, and up to the time when I had received it I had been unaware that Hilton was back in England. Moreover, beyond the fact that his house, "Uplands," was near H—, for which I was instructed to change at New Street Station, Birmingham, I had little idea of its location. But he added "Wire train and will meet at H—"; so that I had no uneasiness on that score.
 
I had contemplated catching the 2:45 from Euston, but by the time I had got my work into something like order, I decided that the 6:55 would be more suitable and decided to dine on the train.
 
Altogether, there was something of a rush and hustle attendant upon getting away, and when at last I found myself in the cab, bound for Euston, I sat back with a long-drawn sigh. The quest of the Prophet's slipper was ended; in all probability that blood-stained relic was already Eastward bound. Hassan of Aleppo, its awful guardian, had triumphed and had escaped retribution. Earl Dexter was dead. I could not doubt that; for the memory of his beautiful accomplice, Carneta, as I last had seen her, broken-hearted, with her great violet eyes dulled in tearless agony—have I not said that it lived with me?
 
Even as the picture of her lovely, pale face presented itself to my mind, the cab was held up by a temporary block in the traffic—and my imagination played me a strange trick.
 
Another taxi ran close alongside, almost at the moment that the press of vehicles moved on again. Certainly, I had no more than a passing glimpse of the occupants; but I could have sworn that violet eyes looked suddenly into mine, and with equal conviction I could have sworn to the gaunt face of the man who sat beside the violet-eyed girl for that of Earl Dexter!
 
The travellers, however, were immediately lost to sight in the rear, and I was left to conjecture whether this had been a not uncommon form of optical delusion or whether I had seen a ghost.
 
At any rate, as I passed in between the big pillars, "The gateway of the North," I scrutinized, and closely, the numerous hurrying figures about me. None of them, by any stretch of the imagination, could have been set down for that of Dexter, The Stetson Man. No doubt, I concluded, I had been tricked by a chance resemblance.
 
Having dispatched my telegram, I boarded the 6:55. I thought I should have the compartment to myself, and so deep in reverie was I that the train was actually clear of the platforms ere I learned that I had a companion. He must have joined me at the moment that the train started. Certainly, I had not seen him enter. But, suddenly looking up, I met the eyes of this man who occupied the corner seat facing me.
 
This person was olive-skinned, clean-shaven, fine featured, and perfectly groomed. His age might have been anything from twenty-five to forty-five, but his hair and brows were jet black. His eyes, too, were nearer to real black than any human eyes I had ever seen before—excepting the awful eyes of Hassan of Aleppo. Hassan of Aleppo! It was, to that hour, a mystery how his group of trained assassins—the Hashishin—had quitted England. Since none of them were known to the police, it was no insoluble mystery, I admit; but nevertheless it was singular that the careful watching of the ports had yielded no result. Could it be that some of them had not yet left the country? Could it be—
 
I looked intently into the black eyes. They were caressing, smiling eyes, and looked boldly into mine. I picked up a magazine, pretending to read. But I supported it with my left hand; my right was in my coat pocket—and it rested upon my Smith and Wesson!
 
So much had the slipper of Mohammed done for me: I went in hourly dread of murderous attack!
 
My travelling companion watched me; of that I was certain. I could feel his gaze. But he made no move and no word passed between us. This was the situation when the train slowed into Northampton. At Northampton, to my indescribable relief (frankly, I was as nervous in those days as a woman), the Oriental traveller stepped out on to the platform.
 
Having reclosed the door, he turned and leaned in through the open window.
 
"Evidently you are not concerned, Mr. Cavanagh," he said. "Be warned. Do not interfere with those that are!"
 
The night swallowed him up.
 
My fears had been justified; the man was one of the Hashishin—a spy of Hassan of Aleppo! What did it mean?
 
I craned from the window, searching the platform right and left. But there was no sign of him.
 
When the train left Northampton I found myself alone, and I should only weary you were I to attempt to recount the troubled conjectures that bore me company to Birmingham.
 
The train reached New Street at nine, with the result that having gulped a badly needed brandy and soda in the buffet, I grabbed my bag, raced across—and just missed the connection! More than an hour later I found myself standing at ten minutes to eleven upon the H— platform, watching the red taillight of the "local" disappear into the night. Then I realized to the full that with four miles of lonely England before me there hung above my head a mysterious threat—a vague menace. The solitary official, who but waited my departure to lock up the station, was the last representative of civilization I could hope to encounter until the gates of "Uplands" should be opened to me!
 
What was the matter with which I was warned not to interfere? Might I not, by my mere presence in that place, unwittingly............