“You’re never going out this afternoon, sir?” she asked falteringly. “Why, the fog’s awful; you can’t see a yard ahead of you!” Unknown to herself, Mrs. Bunting’s voice had risen almost to a scream. She moved back, still holding the tray, and stood between the door and her lodger, as if she meant to bar his way—to erect between Mr. Sleuth and the dark, foggy world outside a living barrier. “The weather never affects me at all,” he said sullenly; and he looked at her with so wild and pleading a look in his eyes that, slowly, reluctantly, she moved aside. As she did so she noticed for the first time that Mr. Sleuth held something in his right hand. It was the key of the chiffonnier cupboard. He had been on his way there when her coming in had disturbed him. “It’s very kind of you to be so concerned about me,” he stammered, “but—but, Mrs. Bunting, you must excuse me if I say that I do not welcome such solicitude. I prefer to be left alone. I—I cannot stay in your house if I feel that my comings and goings are watched—spied upon.” She pulled herself together. “No one spies upon you, sir,” she said, with considerable dignity. “I’ve done my best to satisfy you—” “You have—you have!” he spoke in a distressed, apologetic tone. “But you spoke just now as if you were trying to prevent my doing what I wish to do—indeed, what I have to do. For years I have been misunderstood—persecuted”—he waited a moment, then in a hollow voice added the one word, “tortured! Do not tell me that you are going to add yourself to the number of my tormentors, Mrs. Bunting?” She stared at him helplessly. “Don’t you be afraid I’ll ever be that, sir. I only spoke as I did because—well, sir, because I thought it really wasn’t safe for a gentleman to go out this afternoon. Why, there’s hardly anyone about, though we’re so near Christmas.” He walked across to the window and looked out. “The fog is clearing somewhat; Mrs. Bunting,” but there was no relief in his voice, rather was there disappointment and dread. Plucking up courage, she followed him. Yes, Mr. Sleuth was right. The fog was lifting—rolling off in that sudden, mysterious way in which local fogs sometimes do lift in London. He turned sharply from the window. “Our conversation has made me forget an important thing, Mrs. Bunting. I should be glad if you would just leave out a glass of milk and some bread-and-butter for me this evening. I shall not require supper when I come in, for after my walk I shall probably go straight upstairs to carry through a very difficult experiment.” “Very good, sir.” And then Mrs. Bunting left the lodger.