I listened until these sounds had nearly died away and was just about to emerge from my shelter when I became aware of footsteps approaching from the opposite direction, and as I did not choose to be seen in the act of climbing the railings I decided to remain perdu until this person had passed. These footsteps, too, had a distinctly hurried sound, a fact which I noted with some surprise; but I was a good deal more surprised when the newcomer turned sharply into the entrance, walked swiftly past my ambush, and then, as he approached the corner, suddenly slowed down, advancing cautiously on tip-toe, and finally halted to listen and stare into the obscurity of the lane.

I peered out at this new arrival with an amazement that I cannot describe. Like the first man, he was a complete stranger to me: a tallish, athletic-looking man of about thirty-five, not ill-looking, and having something of a military air; fair-complexioned, with a sandy moustache, but otherwise clean-shaved and dressed in a suit of thick tweed, with no overcoat. I could see these details clearly by the light of the lamp; and even as I was noting them, he disappeared round the corner and I could hear him walking quickly but lightly down the lane.

As soon as he was gone I looked out from my hiding-place and listened attentively. There was no one in sight, nor could I hear any one approaching. I accordingly came forth, and, quickly climbing over the railings, stood for a few moments irresolute. The obviously reasonable thing to do was to make off down Highgate Hill as fast as I could and take the first conveyance that I could get homeward. But the appearance of that second man had inflamed me with curiosity. What was he here for? Was he shadowing me or was he in pursuit of the other man? Either supposition was incredible, but one of them must be true. The end of it was that curiosity got the better of discretion and I, too, started down the lane, walking as fast as I could and treading as lightly as circumstances permitted.

The second man was some considerable distance ahead, for his footsteps came to me but faintly, and I did not seem to be gaining on him; and I took it that his speed was a fair measure of that of the man in front. Keeping thus within hearing of my quarry, I sped on, turning over the amazing situation in my bewildered mind. The first man was a mystery to me, though apparently not to Thorndyke. Who could he be, and why on earth was he taking this prodigious amount of trouble to get rid of a harmless person like myself? For there could be no mistake as to the magnitude of the efforts that he was making. He must have waited outside the studio; followed Marion and me to her home, and there kept a patient vigil of over two hours, waiting for me to come out. It was a stupendous labour. And what was it all about? I could not form the most shadowy guess; while as to the other man, the very thought of him reduced me to a state of hopeless bewilderment.

As my reflections petered out to this rather nebulous conclusion, I halted for a moment to listen for the footsteps ahead. They were still audible, though they sounded somewhat farther away. But now I caught the sound of other footsteps, approaching from behind. Some one else was coming down the lane. Of course, there was nothing surprising in that circumstance, for, after all, this was a public thoroughfare, little frequented as it was, especially after dark. Nevertheless, something in the character of those footsteps put me on the qui vive. For this man, too, was walking quickly—very quickly—and with a certain stealthiness, as if he had rubber-soled boots, and, like the rest of us, was making as little noise as possible.

I walked on at my previous rapid pace, keeping my ears cocked now both fore and aft; and, as I went, my mind surged with wild speculations. Could it be that I had yet another follower? The thing was becoming grotesque. My bewilderment began to mingle with a spice of grim amusement; but still I listened, not without anxiety, to those footsteps from behind, which seemed to be growing rapidly more distinct. Whoever this newcomer might be, he was no mean walker, for he was overtaking me apace; and this fact gave a pretty broad hint as to his size and strength.

I looked back from time to time, but without stopping or slackening my pace, trying to pierce the deep obscurity of the narrow, closed-in lane. But it was a dark winter’s night, and the high fences shut out even the glimmer from the murky sky. It was not until the approaching footfalls sounded quite near that I was able, at length, to make out a smear of deeper darkness on the general obscurity. Then I drew out my pistol and, withdrawing the safety catch, put my hand, grasping it, into my overcoat pocket. Having thus made ready for possible contingencies, I watched the black shape emerge from the darkness until it developed into a tall, portly man, bearing down on me with long, swinging strides, when I halted and drew back against the fence to let him pass.

But he had no intention of passing. As he came up to me, he, too, halted, and, looking into my face with undissembled curiosity, he addressed me in a brusque though not uncivil tone.

“Now, sir, I must ask you to explain what is going on.”

“What do you mean?” I demanded.