Inspector Field swore a good round oath under his breath. He had not looked for an insane folly like this from a well-trained officer who might have been expected to keep his feelings in check. But, as Field sadly reflected, it was useless to anticipate anything rational when a woman came into the case.

Everything had been going beautifully and smoothly a few minutes ago, and now the plot was ruined. Field was anything but a timid man, he had been in too many tight places in his life to know the meaning of the word timidity, but then he had to exercise a certain discretion.

At the same time he was not blind to the fact that his military ally was in considerable danger. The only thing now would be to bluff the whole thing through, to pretend that the game was up and that the house was surrounded with police.

With this intention in his mind, Field crossed the hall and tried the dining-room door. He was not altogether surprised to find the door locked. He listened at the keyhole, but he could not hear anything whatever. Furthermore, the application of an eye to the keyhole disclosed the fact that the room was in darkness. Despite his courage a thrill ran down the spine of the inspector. There was some more than usually devilish work going on here.

"Well, it can't be helped," Field muttered. "It's the fortune of war. One of us has come to grief, and if I stay here I may share the same fate, and I the only one left who knows anything of the secrets of the prison house. I'll run over and get assistance and we'll search the house. After all, my friend the Colonel has only himself to blame."

Without waiting for anything further, Field slipped out by the way he had come. Once in the road, he glanced back at the house, but the whole place seemed to be in pitchy darkness. There was nothing for it now but to make his way to the nearest police station, and get all the assistance possible. There was no trouble at the station across the Common, the mere mention of Field's name being sufficient. A few minutes later half a dozen constables in silent shoes were on their way to the scene of action. There was to be no fuss and bother; they decided to enter quietly and unostentatiously by the larder window, which was done without any noise whatever.

Once the exits were guarded, there was no necessity for further concealment. But though the lights were turned up all over the house and the most careful search made, not a sign of human life could be seen. Everybody had vanished, as if the whole thing had been a dream. Field, standing in the hall and biting his nails, was fain to admit that he was beaten.

How on earth had those people managed to efface themselves in that amazing manner? They had all apparently vanished off the face of the earth. And there was that bulky package too, that Field believed contained the body of Sir Charles. It was long past midnight before Field left the house, having taken precautions not to disturb anything, but even those precautions might have been in vain. For all he knew to the contrary, the place might be watched by its late occupants who were laughing in their sleeves.

"No use staying here any longer, Macklin," he said disgustedly. "I shall have to go back on my tracks once more. Never do I take an amateur into my business plans again. But it looks as if he has paid for his indiscretion. Good night."

It was late into the following afternoon before Field saw Beatrice Darryll again. When he did so, he had nothing to report save failure. Beatrice listened with the greatest interest to what had taken place the night before, but her interest gave place to grave anxiety when she heard what had been the result of Colonel Berrington's daring action.

"Do you suppose that he is in real danger?" Beatrice asked.

"Well, I'm afraid he is," Field admitted. "You see we are dealing with the most daring and clever and unscrupulous gang of scoundrels that I ever encountered. They would not stick at murder or anything else if anybody crossed them. Mind you, it was a most foolish thing for the Colonel to do. Still, he is a soldier and a very resourceful man and he may pull through. Again these people may not have designs on his life; it is just possible that they might keep him a prisoner until their plans had been successfully carried out. Of course when the Colonel was talking to the grey lady to-night I was not supposed to listen. But I have very good ears, and they spoke loudly at times. I gathered that the scoundrel Sartoris was once engaged to a young lady who threw him over. Now it occurred to me that the young lady might give me an idea or two, provided that she is in England at the present moment."

"Why should you think that she is not here?" Beatrice asked.

"Because the engagement took place at Simla. This young lady was staying with her brother and his wife; unfortunately I did not catch the name. The curious part of the affair is that she is a ward of your late father."

Beatrice looked puzzled for a moment. She did not quite understand.

"You mean that my father was guardian under a will or something of that kind?" she asked.

"That's it, miss," Field exclaimed. "We ought to be able to identify the young lady between us, especially as the affair only took place three years ago or so, as I understand. If you will pardon me for saying so, Sir Charles was a very careless gentleman, and hardly the man that a careful parent would choose as a guardian. The young lady's father must have known yours very intimately indeed, or very little, it does not matter which. Still, I don't suppose that Sir Charles had many of these affairs on hand. Now, see if you can recollect anything of the kind happening during the last three or four years, Miss Darryll."

Beatrice thought the matter over carefully for a moment. Her face lighted up presently.

"I fancy that I have it," she said. "Lord Edward DeciÉ, who was a great friend of my father, died about three years ago. The two men did a lot of speculating together, and indeed Lord Edward passed for a shrewd and successful man. When he died I know my father was executor under the will and that he had some control over the Hon. Violet DeciÉ. I never saw the girl, because she went to India with a married brother, and, for all I know she is there still. I understood that she was rather an impulsive kind of girl who did wild things on the spur of the moment. But you can easily inquire."

Field's face expressed a guarded satisfaction. So far he was not very much out.

"That is the young lady, miss," he cried. "I'll put the inquiries on foot at once. And I don't think that I need detain you any longer."

"One minute," Beatrice said. "What about Colonel Berrington? What steps have you taken to find him? Are you going to have that house at Wandsworth watched?"

Field intimated that he was, though in his opinion it was time wasted.

"They will expect something of the kind, you see," he said. "Of course it is a help to me that my presence in the house was not suspected. They may conclude that Berrington was alone in the business, and on the other hand they may not conclude anything of the kind. But, all the same, I am going to have the house carefully watched."

Before the day was out the disappearance of Sir Charles's body was obscured by the strange absence of Colonel Berrington. Field would have kept this latter fact concealed as far as possible, but then Berrington's landlady had been his old nurse, and she was not rational in the matter at all. The authorities had promised to do all they could, though the press accused them of being exceedingly lax in the business. As a matter of fact, Field had given his chiefs an inkling of the situation, so that they were really doing their best all the time. A carefully planned watch on the Wandsworth Common house had come to nothing, but the people there had not yet returned; indeed very little could have been done if they had.

And Field was turning in another direction. He had to trace the young lady who at one time had been engaged to Carl Sartoris, and he had found it a more difficult business than he had anticipated. It was a delicate business, too, calling for tactful manipulation. A somewhat talkative aunt of the young lady was found at length. She took Field for a lawyer who was seeking the Honorable Violet for her own advantage.

"Oh, yes. She has been back from India a long time," Lady Parkstone said. "Violet is a very strange and clever girl. Yes, she has been engaged more than once. But the engagements are always broken off. Violet was always in love with herself. But very clever, as I said before. At one time she bade fair to become quite a famous artist, and she has had stories in the magazines. Her last fad was the stage and that has lasted quite a long time. In fact she is on the stage now."

"In London, my lady?" Field asked. "She is not acting under her own name, of course?"

"No," Lady Parkstone explained. "She is Miss Adela Vane; at present she is playing at the Comedy Opera House. It is just possible that you know the name."

Field knew the name very well. He departed presently well satisfied with the progress that he had made. It was getting quite late by the time he had found out where Miss Vane lodged, but he had time to go back to Scotland Yard again. There, a note from the superintendent of the Wandsworth Police was awaiting him, asking him to go down as soon as possible. The note was vague but it suggested possibilities.

The Wandsworth authorities had not much to say, but they had one detail. Last night one of the men who was told to watch No. 100 had seen something. The windows were all shuttered from top to bottom, each shutter having a little ventilator in it. Field nodded, for he had noticed this himself.

"Very well, then," the superintendent went on. "So far as we know the house is empty. But is it? If so why should a light have been seen last night, behind the little round ventilator? The light came and went, and in a great flashing, dazzling kind of way for half an hour, and then stopped. It was as if a child was playing with the switch of the electric light."

Field nodded and smiled. He looked exceedingly pleased with himself.

"Guess I understand," he said. "Especially as we are seeking for a military gentleman. We'll go as far as Audley Place at once, and investigate. Only we shall have to call at the Post Office and borrow a clerk out of the telegraph department. Come along."

Field volunteered no explanation, and his puzzled colleague followed him out of the office. The telegraph operator and the others stood opposite the house in Audley Place till the patience of all was pretty well exhausted. Then suddenly the light began to flicker in the upper part of the house.

"Isn't that a message of some kind?" Field asked of the telegraph clerk.

"Right," the other said promptly. "That's a kind of telegraph dash and dot system. Whistle a bar from 'when we are married.' Thank you, sir. That's what the gentleman who is sending out those flash signals is asking somebody to do who happens to understand. That last lot of flashes means 'Thank the Lord!' Now he's getting to business. He wants to know who we are before he goes on."

"Can't you give it back again in any way?" Field asked. "Say it's me."

Very loudly the telegraphic operator tapped the pavement with his stick. It sounded quite meaningless, but the light in the house flared up and down in a triumphant kind of way. The flickering began once more and then stopped.

"It's Colonel Berrington," the clerk said presently. "He says you are not to bother about him in the least, as he is quite safe, and so long as he is in there the men are not likely to do anything rash. And here comes the gist of the message. You are to go to Edward Street in the Borough and keep an eye on one of the houses there,—the Colonel doesn't know which. And you are to go at once, he says."