Gurdon waited to hear what his companion was going to say now. He had made up his mind to place himself implicitly in her hands, and let her decide for the best. Evidently, he had found himself in a kind of lunatic asylum, where one inhabitant at least had developed a dangerous form of homicidal mania, and he had a pretty sure conclusion that Vera had saved his life. It was no time now to ask questions; that would come later on.

"I am sure I am awfully grateful to you," Gurdon said. "Who are these people, and why do they behave in this insane fashion? This is not exactly the kind of menage one expects to find in one of the best appointed mansions in the West End."

"I can tell you nothing about it," Vera said. There was a marked coldness in her voice that told Gurdon he was going too far. "I can tell you nothing. One thing you may rest assured of—I am in no kind of danger, nor am I likely to be. My concern chiefly at the present moment is with you. I want you to get back as soon as you can to the Great Empire Hotel, and ease Gerald's mind as to myself."

"I hardly like to go, without you," Gurdon murmured.

"But you must," Vera protested. "Let me assure you once more that I am as absolutely safe here as if I were in my own room. Now, come this way. I dare not strike a light. I can only take you by the hand and lead you to the top of the house. Every inch of the place is perfectly familiar to me, and you are not likely to come to the least harm. Please don't waste a moment more of your time."

Gurdon yielded against his better judgment. A moment or two later, he found himself climbing through a skylight on to the flat leads at the top of the house. By the light of the town he could now see what he was doing, and pretty well where he was. From the leads he could look down into the garden, though, as yet, he could not discern any avenue of escape.

"The thing is quite easy," Vera explained. "The late occupant of the house had a nervous dread of fire, and from every floor he had a series of rope ladders arranged. See, there is one fixed to this chimney. I have only to throw it over, and you can reach the garden without delay; then I will pull the ladder up again and no one will be any the wiser. Please, leave me without any further delay, in the absolute assurance that I shall be back again within an hour."

A few minutes later Gurdon was in the street again, making his way back to the hotel where Venner was waiting for him.

It was a strange story that he had to tell; a very thrilling and interesting adventure, but one which, after all, still further complicated the mystery and rendered it almost unintelligible.

"And you mean to say that you have been actually face to face with our cripple friend?" Venner said. "You mean to say that he would actually have murdered you if Vera had not interfered in that providential manner? I suppose I must accept your assurance that she is absolutely safe, though I can't help feeling that she has exaggerated her own position. I am terribly anxious about her. I have an idea which I should like to carry out. I feel tolerably sure that this picturesque cripple of ours could tell us everything that we want to know. Besides, unless I do something I shall go mad. What do you say to paying the interesting cripple a visit to-morrow night, and forcing him to tell us everything?"

Gurdon shook his head; he was not particularly impressed with the suggestion that Venner had made.

"Of course, we could get into the house easily enough," he said. "Now that I have learned the secret of the cellar, there will be no difficulty about that. Still, don't you think it seems rather ridiculous to try this sort of thing when your wife is in a position to tell you the whole thing?"

"But she would decline to do anything of the kind," Venner protested. "She has told me that her lips are sealed; she has even no explanation to offer for the way in which she left me within half-an-hour of our becoming man and wife. I should almost be justified in forcing her to speak; but, you see, I cannot do that. Therefore, I must treat her in a way as if she were one of our enemies. I have a very strong fancy for paying a visit to our cripple friend, and, if the worst came to the worst, we could convince him that we are emphatically not on the side of Mark Fenwick. At any rate, I mean to have a try, and if you don't like to come in—"

"Oh, I'll come in fast enough," Gurdon said. "You had better meet me to-morrow night at my rooms, say, about eleven; then, we will see what we can do with a view to a solution of the mystery."

At the appointed time, Venner duly put in an appearance. He was clothed in a dark suit and cap, Gurdon donning a similar costume. Under his arm Venner had a small brown paper parcel.

"What have you got there?" Gurdon asked.

"A pair of tennis shoes," was the response. "And if you take my advice, you should have a pair, too. My idea is to take off our boots directly we get into the seclusion of the garden and change into these shoes. Now come along, let's get it over."

It was an easy matter to reach the garden without being observed, and in a very short time the two friends were standing close to the windows of the large room at the back of the house. There was not so much as a glimmer of light to be seen anywhere within. Very cautiously they felt their way along until they came at length to the grating through which Gurdon had made so dramatic an entrance on the night before. He took from his pocket a box of vestas, and ventured to strike one. He held it down close to the ground, shading the tiny point of flame in the hollow of his hand.

"Here is a bit of luck to begin with," he chuckled. "They haven't fastened this grating up again. I suppose my escape last night must have upset them. At any rate, here is a way into the house without running the risk of being arrested on a charge of burglary, and if the police did catch us we should find it an exceedingly awkward matter to frame an excuse carefully, to satisfy a magistrate."

"That seems all right," Venner said. "When we get into the cellar it's any odds that we find the door of the stairs locked. I don't suppose the grating has been forgotten. You see, it is not such an easy matter to get the British workman to do a job on the spur of the moment."

"Well, come along; we will soon ascertain that," Gurdon said. "Once down these steps, we shall be able to use our matches."

They crept cautiously down the stairs into the damp and moldy cellar; thence, up the steps on the other side, where Gurdon lighted one of his matches. The door was closed, but it yielded quite easily to the touch, and at length the two men were in the part of the house which was given over to the use of the servants. So far as they could judge the place was absolutely deserted. Doubtless the domestic staff had retired to bed. All the same, it seemed strange to find no signs of life in the kitchen. The stove was cold, and though the grate was full of cinders, it was quite apparent that no fire had been lighted there for the past four and twenty hours. Again, there was no furniture in the kitchen other than a large table and a couple of chairs. The dressers were empty, and the shelves deprived of their usual burden.

"This is odd," Venner murmured. "Perhaps we shall have better luck on the dining-room floor. I suppose we had better not turn on the lights!"

"That would be too risky," Gurdon said. "However, I have plenty of matches, which will serve our purpose equally well."

On cautiously reaching the hall a further surprise awaited the intruders. There was absolutely nothing there—not so much as an umbrella stand. The marble floor was swept bare of everything, the big dining-room which the night before had been most luxuriously furnished, was now stripped and empty; not so much as a flower remained; and the conservatory beyond showed nothing but wooden staging and glittering glass behind that. A close examination of the whole house disclosed the fact that it was absolutely empty.

"If I did not know you as well as I do," Venner said grimly, "I should say that you had been drinking. Do you mean to tell me that you sat in this dining-room last night, and that it was furnished in the luxurious way you described? Do you mean to tell me that you sat here, opposite our cripple friend, waiting for him to shoot you? Are you perfectly certain that we have made our way into the right house? You have no doubt on that score?"

"Of course, I haven't," Gurdon said, a little hotly. "Would there be two houses close together, both of them with a broken grating over the cellar? I tell you this is the same house right enough. It was just in this particular spot I was seated when the lights went out, and your wife's fertility of resource saved my life. It may be possible that the electric fuses have not yet been repaired. At any rate, I'll see."

Gurdon laid his hand upon the switch and snapped it down. No light came; the solitary illuminating point in the room was afforded by the match which Venner held in his hand.

"There," Gurdon said, with a sort of gloomy triumph. "Doesn't that prove it? I suppose that our cripple took alarm and has cleared out of the house."

"That's all very well, but it is almost impossible to remove the furniture of a great place like this in the course of a day."

"My dear chap, I don't think it has been removed in the course of a day. Didn't you notice just now what a tremendous lot of dust we stirred up as we were going over the house? My theory is this—only three or four of the rooms were furnished, and the rest of the house was closed. When I made my escape last night, the cripple must have taken alarm and gone away from here as speedily as possible. What renders the whole thing more inexplicable is the fact that your wife could explain everything if she pleased. But after a check-mate like this, I don't see the slightest reason for staying here any longer. The best thing we can do is to get back to my rooms and discuss the matter over a whiskey and soda and cigar. But, talking about cigars, will you have the goodness to look at this?"

From the empty grate Gurdon picked up a half smoked cigar of a somewhat peculiar make and shape.

"I want you to notice this little bit of evidence," he said. "This is the very cigar that the cripple gave me last night. I can't say that I altogether enjoyed smoking it, but it was my tip to humor him. I smoked that much. When the white lady came in I naturally threw the end of the cigar into the fireplace. In the face of this, I don't think you will accuse me of dreaming."

More than one cigar was consumed before Venner left his friend's rooms, but even the inspiration of tobacco failed to elucidate a solitary point at issue. What had become of the cripple, and where had he vanished so mysteriously? Gurdon was still debating this point over a late breakfast the following morning, when Venner came in. His face was flushed and his manner was excited. He carried a copy of an early edition of an evening paper in his hand—the edition which is usually issued by most papers a little after noon.

"I think I've discovered something," he said. "It was quite by accident, but you will not fail to be interested in something that appears in the Comet. It alludes to the disappearance of a gentleman called Bates, who seems to have vanished from his house in Portsmouth Square. You know the name of the Square, of course?"

Gurdon pushed his coffee cup away from him, and lighted a cigarette. He felt that something of importance was coming.

"I suppose I ought to know the name of the square," he said grimly. "Seeing that I nearly lost my life in a house there the night before last. But please go on. I see you have something to tell me that is well worth hearing."

"That's right," Venner said. "Most of it is in this paper. It appears that the aforesaid Mr. Bates is a gentleman of retiring disposition, and somewhat eccentric habits. As far as one can gather, he has no friends, but lives quietly in Portsmouth Square, his wants being ministered to by a body of servants who have been in his employ for years. Of necessity, Mr. Bates is a man of wealth, or he could not possibly live in a house the rent of which cannot be less than five or six hundred a year. As a rule, Mr. Bates rarely leaves his house, but last night he seems to have gone out unattended, and since then, he has not been seen."

"Stop a moment," Gurdon exclaimed eagerly. "I am beginning to see daylight at last. What was the number of the house where this Bates lived? I mean the number of the square."

Venner turned to his paper, and ran his eye down the printed column. Then he smiled as he spoke.

"The number of the house," he said, "is 75."

"I knew it," Gurdon said excitedly. "I felt pretty certain of it. The man who has disappeared lived at No. 75, and the place where we had our adventure, or rather, I had my adventure, is No. 74. Now, tell me, who was it who informed the police of the disappearance of Mr. Bates? Some servant, I suppose?"

"Of course; and the servant goes on to suggest that Mr. Bates had mysterious enemies, who caused him considerable trouble from time to time. But now I come to the interesting part of my story. At the foot of the narrative which is contained in the Comet, that I hold in my hand, is a full description of Mr. Bates."

"Go on," Gurdon said breathlessly. "I should be little less than an idiot if I did not know what was coming."

"I thought you would guess," Venner said. "A name like Bates implies middle age and respectability. But this Bates is described as being young and exceedingly good looking. Moreover, he is afflicted with a kind of paralysis, which renders his movements slow and uncertain. And now you know all about it. There is not the slightest doubt that this missing Bates is no other than our interesting friend, the good-looking cripple. The only point which leaves us in doubt is the fact that Mr. Bates is a respectable householder, living at 75, Portsmouth Square, while the man who tried to murder you entertained you at No. 74, which house, now, is absolutely empty. We need not discuss that puzzle at the present moment, because there are more important things to occupy our attention. There can be no doubt that this man who calls himself Bates has been kidnapped by somebody. You will not have much difficulty in guessing the name of the culprit."

"I guess it at once," Gurdon said. "If I mention the name of Mark
Fenwick, I think I have said the last word."