Field walked away thoughtfully from the office of Mr. Fleming. He was a little pleased to find that the lawyer took the same view of the mystery as himself. There was a great deal to be done yet. It was getting very late indeed before Field made his way once more in the direction of Wandsworth. He had an important paper in his pocket, and he had given directions for two of his most trusted men to meet him outside No. 100, Audley Place, by eleven o'clock.

But those other men had other tasks to perform first, and they might be some time yet. With this knowledge in his mind, Field repaired to the garden in front of the house and there decided to wait for developments. It was not a cold night, the bushes in the garden were thick, and Field felt that he would be just as well there as anywhere else. His patience was not unduly tried. He chuckled slightly to himself as he saw Beatrice arrive. He had a pretty shrewd idea what she was here for.

"The old fox is not quite certain of his goal," he told himself. "He thinks he has got everything in his grip—that the forged deed will do the mischief, but perhaps there are other papers. That is why he has sent for Mrs. Richford. We shall see."

If Sartoris had known what reposed in Field's breast pocket he would not have been quite so easy in his mind. But he did not know it, and Field did not know what was transpiring inside the house. He waited a little longer till Mary Sartoris came up. She seemed to be greatly agitated about something; she stood in the garden hesitating. A little later, and she was joined by Mark Ventmore. Field was glad to see so valuable an ally here.

From his hiding-place Field could hear all that passed. It was a satisfaction to be able to gather up such a deal of information. Richford would have to come into the net presently, and Richford was in England, which was more than Field had expected. Of course, with everybody else, he had heard of the famous diamonds that Richford had given to his wife, and supposed that before now the diamonds had been turned into money. Into funds, Richford would have had a good chance of getting away; as it was, he must still be in London.

"So that fellow is still here," Field chuckled. "Did she say Edward Street? The very house that I have my eye on. We will bag all the birds. Hullo, here come some more!"

Mark and Mary Sartoris drew back as the man and woman respectively called Reggie and Cora came up. They had their listeners, but they did not know it. Perhaps, if they had, they would not have made their plans quite so openly. As it was, they had laid bare the whole of their new scheme to the quickest ears in London. Field slipped from his hiding-place as Reggie and Cora closed the front door behind them. Mary gave a little scream.

"There is no occasion for alarm—at least, as far as you are concerned, Miss Sartoris," Field said. "I have heard everything that those people said."

"This is Inspector Field of Scotland Yard," Mark said.

Mary's lips quivered, but she said nothing. Her own instincts told her what Field was doing here. She had always felt that the bubble must burst some day—she had always known that her noble efforts were altogether in vain. And yet she would have gone on sacrificing herself to save Carl Sartoris from the fate that was inevitable.

"Are you down here on any special business?" Mark asked.

"On business connected with the disappearance of Sir Charles Darryll and other matters," Field said. "The one thing contains the other. But you need not have the smallest apprehension for the safety of Mrs. Richford and her diamonds. She is not going to lose them."

"How did you know that she had those diamonds in her pocket?" Mary asked.

"You forget that I have been hiding here," Field explained. "Like yourself, I heard every word that passed just now. Every moment I expect to have two of my most trusted men here. Directly those two emerge from the house and get into the road, they will be arrested. In my business I often find that when you are looking for one bird you frequently find another. Mr. Reggie and Miss Cora are old friends of mine and the Paris police. They are very clever at disguises; they work together, she as a countess, and he as a general officer. Both of them were on the stage and both would have made very good names, but the honest rÔle was too dull for them. You may rest assured that those two will be out of the way before daylight."

Mary listened with mixed feelings. She felt that in a measure she was mainly responsible for what was going to happen. It looked as though it would be an eventful evening.

"Well, we can't stand here all night," Mark said impatiently. He was vaguely frightened for Beatrice, in the house with those rascals. "I can help you. You and I together would be a match for the lot of them. What do you say to try?"

But Field had no feeling that way at all. The cool, shrewd officer did not rush things in that fashion. He had his birds secured and he could afford to wait.

"I cannot possibly permit you to interfere with my plans, sir," he said coldly. "You must recollect that I am responsible to the authorities, and that I have my reputation to think of. In my pocket I have a warrant for the arrest of certain people, and that being the case——"

"For my brother! for Carl Sartoris?" Mary gasped. "Oh, is that really so?"

"It would be no kindness to conceal the fact," Field said in a gentle tone. "No, I cannot permit you to enter the house. The thing is absolutely inevitable, and you could not possibly prevent it. A cripple like your brother could not escape me, and any hasty action of yours might mean the escape of the other two. I am exceedingly sorry, Miss Grey."

Mary started as she heard her own name from the lips of the inspector. The expression told her that he knew everything. The blow had fallen at last, as Mary always knew that it would fall, but it was none the less bitter for that. Tears rolled down her cheeks, but she said nothing further. Mark looked at her with distress in his eyes; he and Field exchanged glances.

"This must be very painful to you, miss," the latter went on. "By staying here you can do us no good—you are only giving yourself unnecessary pain. Is there any house you can go to, any place where you can stay for the night? A hotel?"

"I have no friends and no money," Mary said through her tears. "Since coming to England I have given myself wholly to my brother. I have done my best to make the path smooth for him and I have failed. It was no fault of mine that Sir Charles——"

"That Sir Charles was not warned," Field said hastily. "Don't say any more, please. Don't place yourself in such a position that I shall have to call you as a witness."

Mary swallowed down her choking sobs. Two figures stole across the street, and Field gave a low whistle. His two trusty subordinates had come at last. As they passed by the gate Field strode across to them and gave them their instructions. Mark turned to Mary.

"Pray let me be your banker," he said. "Let me provide the money so that you——"

"But I cannot," Mary protested. "I dare not. You would never see the money again, and like all good and generous people, you are as poor as I am myself."

"That remark may have applied to my affairs yesterday, but it certainly does not to-day," Mark said eagerly. "I told you that I have been to see my father who has been very ill lately. As he lay in bed, with no friends to come and see him—for he has been a hard and selfish man—he grew to see things in a different light. He sent for me. He was rather impressed by the tale that I had managed to do without his assistance and that I was making a name for myself. I told him everything, and we are quite good friends again. He insisted upon making me an allowance of £1,500, and as the thought of it did him good, I did not protest. After that, will you let me help you? I know how good you are, and how you have suffered."

"I am more than grateful," Mary said in a choked voice. "It is kind of you, but I cannot take any advantage of your offer; I must stay till the end."

"And go through all the misery of it," Mark protested. "You know that all those people will sleep in jail to-night. Why should you witness the arrest? Let me take you to some quiet hotel and arrange for your accommodation there."

But Mary shook her head resolutely. She was not going to leave till she was forced to. Mark ceased his pleadings as Field came back to them.

"If you would only let me go into the house," Mary said. "I have my own key, and I shall not make the slightest noise. They do not require me! if I put my head inside the study I should at once be ordered out again. Let me go to my own room."

Field hesitated for a moment. It was not the first time he had met a good woman whose life was bound up with that of a criminal, and he had experience of what those women could do in the hour of peril. And yet he hesitated because Mary's prayer was passionate and sincere. But it was only for a moment, then he became a police officer again.

"I could not allow it," he said. "If it came to the ears of my superiors, I should suffer. And I have a wife and family to think of. In minutes of temptation such as you ask me to put before you, women are capable of anything for the sake of those they love. Besides, you would not have me do a thing that is wrong in the eyes of my employers?"

Mary was silent. Her own sense of justice showed her that Field was right. But nothing would induce her to go away, so long as there was anything like hope remaining. She might get a chance still to whisper one word of warning. And if it came she would not hesitate. She had not been placed on her parole so far.

She turned away to wipe her shining eyes, and as she did so the door opened and Berrington crept out. His face was full of excitement, his lips were white.

"Glad to find you here," he said. "I was going to try and find a messenger. I could not leave the house for very long, considering that——"

He paused significantly, with his eyes on Mary. Evidently Berrington had made some great and startling discovery, or he would not have been so dreadfully agitated. Even in the moment of her awful sorrow, Mary could find time to speak and think of others.

"I am in a great measure responsible for this," she said. "Philip, Beatrice Richford is in the house; she has a valuable parcel of diamonds in her pocket; those thieves there know it. Go to her assistance at once; see that she is safe from harm. If anything happens to her I shall never forgive myself. Why don't you go at once?"

"I am sorry," Berrington stammered. He seemed quite dazed and confused. "I have no doubt that Mrs. Richford will be perfectly safe, seeing that assistance is at hand. Indeed, I let her know that I was in the house so that she should not be unduly frightened. But there are other matters of far greater importance than that. Sir Charles Darryll——"

"I thought we should come to Sir Charles Darryll," Field cut in swiftly. "But we need not discuss that matter here and now. Do you want me?"

Field asked the question with a strange ring in his voice. Berrington wondered—he was rapidly regaining complete possession of himself. He moved towards the house.

"In a few minutes," he said. "Wait till I give you the signal. Thank goodness, you were so close by."

Berrington passed into the house again and closed the door behind him.