At the side of the door we halted a moment, and I saw Oakes give the German a twenty-dollar bill. "Remember," he said, "not a word." We caught our train after a long drive to the east, and back over the Harlem River. When we seated ourselves in the sleeper, Oakes turned to me quietly. "Please remember, Stone, that you are a possible buyer, and that I am Charles Clark, agent for the owner of the Mark Mansion. We have had a pleasant evening together so far, have we not?" He smiled in his quiet, unruffled manner as he spoke. "Yes--rather active," I said. "I presume those other fellows are thinking so too, probably." "Only the last two," said Oakes; "my men are home by this time." Shortly after midnight we arrived at the station at the foot of the hill which hid the beautiful town of Mona. "Keep your senses alert," said Oakes as we left the train, "for we are now in the region of uncertainty. We had better not walk to the hotel, although it is only about a mile. The hour is too late." The solitary hackman, seeing us approach, roused himself from his sleepy lethargy and soon we were slowly ascending the hill. The well-kept road was lighted here and there by electricity, an agreeable witness to the civilization around us. I saw Oakes place his weapon in his outside overcoat pocket--as he said, the most convenient place for it to rest, clad as we were. The action was a vivid reminder of the experiences of his last visit, and of the caution of the man. Without further adventure of any kind we arrived at the little hotel, with its sleepy night clerk and its gloomy office. This opened right on the sidewalk by means of a large wooden door, hung a low step above the pavement, and fitting so poorly in its frame that the rays of the light from within sought exit beneath it. _CHAPTER V_ _The Letter_ While Oakes and I were in the first stages of our journey, Dr. Moore stood in his back office at the close of business hours, wondering if the adventure that Oakes had so well described to us could in any way have been originated by other than physical forces. Moore was a deep student of mental phenomena. He had on more than one occasion heard histories of terrible tragedies, so real in their wording that the picture conveyed was the practical guarantee of their origin at human hands; but, nevertheless, these histories had been proved to be but the imaginings of a diseased mind--products of a delusion. In every other respect the narrators had been, in appearance at least, perfectly sane individuals. While he hesitated to think that Oakes might have been suffering from an overworked brain at the time, still he knew that it was not impossible. The struggles that the servants had heard had been those of Oakes; the actual evidences so far of assault were vague. Oakes was in a partially unconscious condition, to be sure; but what evidence of violence was that?