There was no guess-work about this, neither had the detective been able to distinguish anything feminine about the knock. Over the door was a peculiar little contrivance, which by means of several small mirrors would tell the occupant of the office who summoned him—a useful affair under the circumstances, as the detective might at some time have a visitor bent on taking his life, and under such circumstances he would be warned. Jumping to his feet he approached the door—had it been a man he probably would have sung out: “Come in,” and been done with it. A lady stood there. She was deeply veiled, and yet there was that about her dress that bespoke the lady. Darrell saw this at the first glance, and also judged from her figure that she was young. “Is this the office of Mr. Darrell?” she asked, in low, pleasing tones. “Yes, madam,” replied the other, respectfully. “Is he in?” “I am Eric Darrell, at your service. If you wish to see me on business will you come in?” He stepped aside as he spoke. “Thank you, I will.” As the lady entered the room, the detective closed the door, and with the pressure of his thumb secured it so that no one could enter without knocking. It was not his intention to be rudely interrupted in his interview—he had from time to time all sorts of visitors, and did not mean that one of the men he employed should come in upon them while they were engaged in talking. The lady had already seated herself, and seemed to be looking around the room, through her veil, with considerable interest. Perhaps it was her first visit to the office of a detective, and she was taken with the strange assortment of mementoes that hung around the room. Eric Darrell swept his eyes about him, and something akin to a smile came over his face as he viewed his curiosity shop—there were scores and scores of murderous tools and ingenious contrivances, each of which was connected with some crime or criminal in the past history of New York, and in the pursuit of his chosen business he had been brought into connection with the affair or the individual. The detective was a little proud of his collection, as well as the Rogue’s Gallery over the desk, where some hundreds of faces were represented, many extremely brutal and some good-looking, while the pictures of women were not infrequent. “My clerk is out this afternoon, madam—we are quite alone, so that you may speak without any fear of being overheard,” he said, as he took a chair, and sat down facing his unknown client. “I am glad of that, Mr. Darrell, for what I have to say to you must be kept a dead secret.” The detective was more than ever convinced that he had to deal with a young woman—her figure was exceedingly pleasing, and her voice a sympathetic one.