“But tell me, Mabel; tell me more of her,” I urged. “Ever since my strange marriage, under circumstances of which you are apparently well aware, I have been groping in the dark, seeking always, but finding nothing. I have tried to penetrate the mystery of her past, but, alas! cannot.”

“Ah! that is not surprising. The precautions taken to prevent you ascertaining the truth are indeed elaborate, every possible contingency having been provided for.”

“Do you mean that I am never to obtain the knowledge I seek; that I am always to remain in ignorance?”

“With Markwick’s sanction you will never know. He is implicated far too deeply.”

“How implicated?”

“I am not yet in possession of the whole of the facts. If I were I should not be compelled, as I now am, to purchase his silence by risking my own reputation. But it is for that very reason I sought you this morning. If I dared, I would tell you all I know of Sybil; but by doing so I should bring upon my head the exposure that I dread.”

What, I wondered, was the nature of the secret which she feared Markwick would betray? Only one solution of the problem occurred to me, and it rooted itself firmly in my mind. The secret was none other than the fact that she had either lured young Sternroyd to his death or had actually fired the fatal shot herself. The thought was startling, but her words and manner showed conclusively her guilt, and in those brief moments, during which a silence fell between us, I told myself that two persons must be associated in the murder of the young millionaire, and that their names were Mabel, Countess of Fyneshade, and Captain John Bethune.

Hers was unmistakably the face of one whose conscience was borne down by a guilty secret, and I felt instinctively to shrink from her as next second she stretched forth her gloved hand and laid it gently on my arm.

“I am powerless, Stuart, utterly powerless to tell you what you desire to know about the woman who was so strangely married to you,” she said. “For reasons already explained I am forced to remain silent; but further, I cast myself upon your generosity. I beseech you once again to help a woman friendless among enemies, who seek her degradation and social ruin.”

“Well, what do you want?” I asked rather roughly.