We arrived at Willow Road, Hampstead, at ten minutes to twelve. Telling Dick to remain in the taxi, I got out and rang the bell. The door was opened by a maid I had not seen before, and when I inquired for Miss Challoner she stared at me blankly—indeed, as I thought, suspiciously. "Nobody of that name lives here," she said curtly. Quickly I glanced up at the number on the door. No, I had not mistaken the house. "She is staying here," I said, "staying with Mrs. Stapleton." "With Mrs. who?" "Mrs. Stapleton." "You have mistaken the house. There's nobody of that name here." "Well, Mr. Gastrell, then," I said irritably. "Ask Mr. Gastrell if I can see him." "I tell you, sir, you've come to the wrong house," the maid said sharply. "Then who does live here?" I exclaimed, beginning to lose my temper. The maid looked me up and down. "I'm not going to tell you," she answered; and, before I could speak again, she had shut the door in my face. CHAPTER XX PRESTON AGAIN I had seen Dick off at Paddington, after asking the guard to keep an eye on him as far as Windsor, and was walking thoughtfully through the park towards Albert Gate, when a man, meeting me where the paths cross, asked if he might speak to me. Almost instantly I recognized him. It was the man who had followed Preston, Jack, and myself on the previous night, and been pointed out to us by Preston. "I trust," he said, when I had asked him rather abruptly what he wanted to speak to me about, "that you will pardon my addressing you, sir, but there is something rather important I should like to say to you if you have a few minutes to spare." "Who are you?" I inquired. "What's your name?" "I would rather not tell you my name," he answered, "and for the moment it is inadvisable that you should know it. Shall we sit here?" he added, as we came to a wooden bench. I am rather inquisitive, otherwise I should not have consented to his proposal. It flashed across me, however, that whereas there could be no harm in my listening to what he wished to say, he might possibly have something really of interest to tell me. "You are probably not aware," he said, when we were seated, "that I followed you last night from a house in Warwick Street, Regent Street, to a restaurant in Gerrard Street, Soho; thence to Willow Road, near Hampstead Station; and thence to South Molton Street Mansions. Two gentlemen were with you." "And may I ask why you did that?" I said carelessly, as I lit a cigarette.