"Are you out of work, Wigan?" he asked, looking at the clock. I did not want him to think I had come with any deliberate intention, so I answered casually: "No. As a fact I am rather busy. I came out to Chelsea to think. Chelsea air is rather good for thinking, you know." "It used to be," he answered. "I'm glad I have given up criminal hunting, Wigan." "I still find excitement in it," I answered carelessly, "and really I think criminals have grown cleverer since your time." He looked at me sharply. I thought the remark would pique his curiosity. "That means you have had some failures lately." "On the contrary, I have been remarkably successful." "Glad to hear it," he returned. "What makes you say criminals are more clever then?" "The Queen's Square Mystery." "I don't read the papers as carefully as I did," he remarked. "It only happened this morning," I answered. "I daresay you noticed that Sir Grenville Rusholm died the other day. Some one has stolen his body, that is all." "Stolen his--" "Yes, it is rather a curious case, but we won't talk about it. I know that sort of thing doesn't interest you now." I talked of other things--anything and everything--but I noted that he was restless and uninterested. "What did Sir Grenville die of?" he asked suddenly. "A sudden and most unexpected collapse after influenza." "And the body has been stolen?" "Yes." "I should like to hear about it, Wigan." I hesitated until he began to get angry, and then I told him the story as I have told it here. I had just finished when Zena came in. "You, Murray! What has brought you here at this hour of the day?" she asked in astonishment. "Two pieces of lead," murmured Quarles. "A case! Have you got interested in a case, dear? I am glad. What is the mystery, Murray?" "Where is the key of my room, Zena?" Quarles asked. She took it from the drawer in a cabinet. "I am not going to begin again," said the professor, "but this--this is an exception. Come with us, Zena. Come and ask some of your absurd questions. I wonder whether my brain is atrophied. There are cleverer criminals than there used to be in my time, are there, Wigan? We shall see." He led the way to the empty room at the back of the house, muttering to himself the while, and Zena and I smiled at each other behind his back as we followed him. He was like an old dog on the trail again, and I did not believe for a moment this case would be an exception. "Tell the story, Wigan," he said when we were seated. "All the details, mind, great and small." So I went through the facts again. "I made a careful study of the house and garden," I went on. "The Lodge is a corner house, the garden is small, and a garage with an opening into the other road--Connaught Road--has been built there. A 'Napier' car was in the garage." "Did you see the chauffeur?" asked Quarles.