"It is really too bad of Tibbie, don't you think so? She ought to draw the line at disappearing like this. She may have met with foul play for all one knows. It seems, according to Mason, that she took a lot of her jewellery with her on the night she left Ryhall in the car." "Does Mason know or suspect anything?" I asked quite innocently. "Nothing, as far as I'm aware. The detectives have made every inquiry, but discovered nothing." Then he added, in a voice which sounded to me to convey a distinct hidden meaning, "They've been just as successful regarding Tibbie as they have been in the case of the mystery up in Charlton Wood." I said nothing. My object was to allow him to do all the talking. At Boodle's we sat down to an excellent dinner, though it was rather late. As he sat before me, his elbows on the table and his hands clasped as he chatted, I looked into his face and wondered what were the inner workings of his ingenious mind. He made no mention of his call at that obscure hotel in Lambeth in search of Tibbie, but merely expressed a fervent hope that the jewellery which she had carried with her when she left on her midnight motor-drive had not been the cause of any attempt upon her by malefactors. In order to watch his attitude I suddenly exclaimed,-- "That affair in Charlton Wood seems still a mystery. And yet I hear," I added, making a bold shot, "that the police have at last found a clue." His countenance remained perfectly unchanged. He merely responded,-- "I hope they have. It was a dastardly thing. The poor fellow must have been shot treacherously--murdered in cold blood. Jack is most anxious to find the culprit, and I don't wonder. It isn't nice to have a murder committed upon one's own estate." "It's curious that the man has not yet been identified," I said, regarding him keenly. "And has it not also struck you as strange that Tibbie should suddenly disappear on the night of the murder?" he asked, his eyes fixed upon mine. "No," I replied, quite unconcernedly. "I had never given that a thought. It is curious, now that you recall it. A mere coincidence, of course." "Of course," he said, pouring me out a glass of still Moselle. His air of refinement was irritating. Then, after a brief silence, he said,-- "Do you know, Hughes, I can't help thinking that something serious has happened to Tibbie. The letter Lady Scarcliff received was posted in Glasgow, but of course that was only a blind. She's in London somewhere. I told Wydcombe to-day that they ought to advertise and offer a reward for her." His suggestion suddenly gave me an idea. In the pockets of the unknown man in Charlton Wood I had found the key to a cipher which he had evidently used to correspond with his friends. Why should I not through the medium of the papers open up some correspondence? Would anyone reply?