The only person who could elucidate the mystery was Sonia, the pretty girl who had been denounced by Renouf as a murderess, and who was now in hiding in far-off Russia, in some out-of-the-world place where I could never hope to find her. If she were clever enough to elude the combined vigilance of the detective force of Europe, as undoubtedly she had done, there was but little hope that I could ever run her to earth. The mystery had, by Ella's flight, been increased rather than explained, for the more I pondered the more deeply-rooted became the conviction that she had decamped because she had cause to fear some strange development that would lead to her exposure and shame. After a time I roused myself, and taking from the broken escritoire the other letters it contained, five in number, examined them eagerly beneath the light. All were in the same hand, a heavy masculine one, written evidently with a quill. One by one I read them, finding that they contained appointments, which fully bore out her maid's suspicions. "_My dear Ella_," one ran, "_to-morrow I shall be on the departure platform at King's Cross Station at 11:30. I have good news for you. Come.--X_." Another regretted the writer's inability to keep an appointment, as he had been called unexpectedly to Paris, and was compelled to leave by the night mail from Charing Cross. He, however, promised to return in three days, and gave her the Grand Hotel as his address if she found it necessary to telegraph. Strangely enough, the letters contained no endearing terms either at their commencement or conclusion. Formal and brief, they all related to appointments at various places in London where two persons might meet unnoticed by the crowd, and all were signed by the single mysterious initial. I stood with them in my hand for a long time, puzzled and hesitating, then placing them carefully in my pocket, together with the secret document I had so unexpectedly unearthed, I crammed on my hat and hastily drove to Pont Street. The house was in darkness, save for a light in the basement, and in answer to my summons, after a lapse of some minutes a tall, gaunt, woman in rusty black appeared in the area below. I was surprised at being thus met by a stranger, but inquired for Mrs Laing. "Mrs Laing ain't at 'ome, sir," answered the woman, looking up and speaking with a strong Cockney twang. "Not at home?" I exclaimed, surprised. "Where is she?" "She's gone abroad somewheres, but I don't know where," the woman answered. "She's sold all her valuables, discharged the servants, and left me 'ere as 'ouse-keeper." "When did she go?" I asked. "This morning. I answered an advertisement in the _Chronicle_ yesterday, and entered on my duties 'ere to-day. Quick, ain't it?" The rapidity of her engagement I was compelled to admit, but proceeded to make further inquiry whether Mrs Laing's daughter had been there.