It did not need a word from Lady Delahaye to acquaint me fully with what had happened.  Indeed, my only wonder had been that this knowledge had not come to her before.  She greeted me with a smile, but her face was full of purpose.

“Where is he?” she asked simply.

“Not here,” I answered.

She seated herself, and began to unpin the travelling veil from her hat.

“So I perceive,” she remarked.  “He will return?”

“Yes,” I admitted, “he will return.”

She folded the veil upon her knee and looked across at me thoughtfully.

“What an idiot I have been!” she murmured.  “After all, that emerald necklace might easily have been mine.”

“I am not so sure about that,” I answered.  “I think I know what is in your mind, but I might remind you that suspicion is one thing and proof another.”

“The motive,” she answered, “is the difficult thing, and that is found.  I suppose the police are good for something.  They should be able to work backwards from a certainty.”

“Are you,” I asked, “going to employ the police?  Don’t you think that, for the good of everyone, and even for your husband’s own sake, the thing had better remain where it is?”

She laughed scornfully.

“You would have me let the man go free who shot another in the back treacherously and without warning?” she exclaimed.  “Thank you for your advice, Arnold Greatson.  I have a different purpose in my mind.”

I moved my chair and drew a little nearer to her.

“Lady Delahaye ­” I began.

“The use of my Christian name,” she murmured, “would perhaps make your persuasions more effective.  At any rate, you might try.  I have never forbidden you to use it.”

“If you have any regard for me at all, then, Eileen,” I said, “you will think seriously before you take any steps against Monsieur Feurgeres.  Remember that he had, or thought he had, very strong reasons for acting as he did.  Looking at it charitably, your husband’s proceedings were open to very grave misconstruction.  There will be a great deal of unpleasant scandal if the story is raked up again, and Isobel’s whole history will be told in court.  How will that suit the Archduchess?”

“Not at all,” Lady Delahaye admitted frankly; “but the Archduchess is not the only person to be considered.  You seem to forget that this is no trifling matter.  It is a murderer whom you are shielding, the man who killed my husband whom you would have me let go free.”

“Technically,” I admitted, “not actually.  Your husband did not die of his wound.  He was in a very bad state of health.”

“I cannot recognize the distinction,” Lady Delahaye declared coldly.  “He died from shock following it.”

“Consider for a moment the position of Monsieur Feurgeres,” I pleaded.  “Isobel was the only child of the woman whom he had dearly loved.  The care of her was a charge upon his conscience and upon his honour.  Any open association with him he felt might be to her detriment later on in life.  All that he could do was to watch over her from a distance.  He saw her, as he imagined, in danger.  What course was open to him?  Forget for the moment that Major Delahaye was your husband.  Put yourself in the place of Feurgeres.  What could he do but strike?”

“He broke the law,” she said coldly, “the law of men and of God.  He must take the consequences.  I am not a vindictive woman.  I would have forgiven him for making a scene, for striking my husband, or taking away the child by force.  But he went too far.”

“Have you,” I asked, “been to the police?”

“Not yet.”

I caught at this faint hope.

“You came here to see him first?  You have something to propose ­some compromise?”

She shook her head slowly.

“Between Monsieur Feurgeres and myself,” she said, “there can be no question of anything of the sort.  There is nothing which he could offer me, nothing within his power to offer, which could influence me in the slightest.”

“Then why,” I asked, “are you here?”

“To see you,” she answered.  “I want to ask you this, Arnold.  You wish Monsieur Feurgeres to go free.  You wish to stay my hand.  What price are you willing to pay?”

I looked at her blankly.  As yet her meaning was hidden from me.

“Any price!” I declared.

Then she leaned over towards me.

“What is he to you, Arnold ­this man?” she asked softly.  “You are wonderfully loyal to some of your friends.”

“I know the story of his life,” I answered, “and it is enough.  Besides, he is an old man, and I fancy that his health is failing.  Let him end his days in peace.  You will never regret it, Eileen.  If my gratitude is worth anything to you ­”

“I want,” she interrupted, “more than your gratitude.”

We sat looking at each other for a moment in a silence which I for my part could not have broken.  I read in her face, in her altered expression, and the softened gleam of her eyes, all that I was expected to read.  I said nothing.

“It is not so very many years, Arnold,” she went on, “since you cared for me, or said that you did.  I have not changed so much, have I?  Give up this senseless pursuit of a child.  Oh, you guard your secret very bravely, but you cannot hide the truth from me.  It is not all philanthropy which has made you such a squire of dames.  You believe that you care for her ­that child!  Arnold, it is a foolish fancy.  You belong to different hemispheres; you are twice her age.  It will be years before she can even realize what life and love may be.  Give it all up.  She is in safe hands now.  Come back to London with me, and Monsieur Feurgeres shall go free.”

“Monsieur Feurgeres, Madame, thanks you!”

He had entered the room softly, and stood at the end of the screen.  Lady Delahaye’s face darkened.

“May I ask, sir, how long you have been playing the eavesdropper?” she demanded.

“Not so long, Madame, as I should have desired,” he answered, “yet long enough to understand this.  My young friend here seems to be trying to bargain with you for my safety.  Madame, I cannot allow it.  If your silence is indeed to be bought, the terms must be arranged between you and me.”

She looked at him a trifle insolently.

“I have already explained to Mr. Greatson,” she remarked, “that bargaining between you and me is impossible because you have nothing to offer which could tempt me.”

“And Mr. Greatson has?”

“That, Monsieur,” she answered, “is between Mr. Greatson and myself.”

Monsieur Feurgeres stood his ground.

“Lady Delahaye,” he said, “I want you to listen to me for a moment.  It is not a justification which I am attempting.  It is just a word or two of explanation, to which I trust you will not refuse to listen.”

“If you think it worth while,” she answered coldly.

He shrugged his shoulders.

“Who can tell!  I have the fancy, however, to assure you that what took place that day at the Cafe Grand was not the impulsive act of a man inspired with a homicidal mania, but was the necessary outcome of a long sequence of events.  You know the peculiar relations existing between Isobel and myself.  I had not the right to approach her, or to assume any overt act of guardianship.  Any association with me would at once have imperilled any chance she may have possessed of being restored to her rightful position at Waldenburg.  I accordingly could only watch over her by means of spies.  This I have always done.”

“With what object, Monsieur Feurgeres?” Lady Delahaye asked.  “You could never have interfered.”

“The care of Isobel ­the distant care of her ­was a charge laid upon me by her mother,” Feurgeres answered.  “It was therefore sacred.  I trusted to Fate to find those who might intervene where I dared not, and Fate sent me at a very critical moment Mr. Arnold Greatson.  Lady Delahaye, to speak ill of a woman is no pleasant task ­to speak ill of the dead is more painful still.  Yet these are facts.  The Archduchess was willing to go to any lengths to prevent Isobel’s creditable and honourable appearance in Waldenburg.  It was the Archduchess who, after what she has termed her sister’s disgrace, sent Isobel secretly to the convent, and your husband, Lady Delahaye, who took her there.  It was your husband who brought her away, and it was the announcement of his visit to the convent, and an ill-advised confidence to a friend at his club in Paris, which brought me home from America.  I will only say that I had reason to suspect Major Delahaye as the guardian of Isobel ­even the Archduchess was ignorant of the position which he had assumed.  Since I became a player there are many who forget that my family is noble.  Major Delahaye was one of these.  He returned a letter which I wrote to him with a contemptuous remark only.  My friend the Duc d’Autrien saw him on my behalf.  From him your husband received a second and a very plain warning.  He disregarded it.  Once more I wrote.  I warned him that if he took Isobel from the convent he went to his death.  That is all!”

There was a silence.  Lady Delahaye was very pale.  She looked imploringly at me.

“Monsieur Feurgeres,” she said, “I am not your judge.  I do not wish to seem vindictive.  Will you leave me with Mr. Greatson for a few minutes?”

“Madame, I cannot,” he answered gravely.  “Apart from the fact that I decline to have my safety purchased for me, especially by one to whom I already owe too much, it is necessary that Mr. Greatson leaves this house within the next quarter of an hour.”

I sprang to my feet.  I forgot Lady Delahaye.  I forgot that this man’s life and freedom rested at her disposal.  The great selfishness was upon me.

“I am ready!” I exclaimed.

Lady Delahaye looked, and she understood.  Slowly she rose to her feet and crossed the room towards the door.  I was tongue-tied.  I made no protest ­asked no questions.  Feurgeres opened the door for her and summoned his servant, but no word of any sort passed between them.  Then he turned suddenly to me.  His tone was changed.  He was quick and alert.

“Arnold,” he said, “the rest is with you.  They are taking her to the convent.  Madame Richard is here, and the Cardinal de Vaux.  They have a plot ­but never mind that.  If she passes the threshold of the convent she is lost.  It is for you to prevent it.”

“I am ready!” I cried.

He opened a desk and tossed me a small revolver.

“Estere waits below in the carriage.  He will drive with you to the station.  You take the ordinary express to Marcon.  There an automobile waits for you, and you must start for the convent.  The driver has the route.  Remember this.  You must go alone.  You must overtake them.  Use force if necessary.  If you fail ­Isobel is lost!”

“I shall not fail!” I answered grimly.

“Bring her back, Arnold,” he said, with a sudden change in his tone.  “I want to see her once more.”

I left him there, and glancing upwards from the street as the carriage drove off, I waved my hand to the slim black figure at the window, whose wan, weary eyes watched our departure with an expression which at the time I could not fathom.  It was not until I was actually in the train that I remembered what Lady Delahaye’s silent departure might mean for him.