“I don’t think he goes to Stepney, though I don’t know whether I ought to talk about his business to a stranger; but if you want him particularly, I should imagine you would find him at Slough. I’m a monthly nurse,” she said, “and I’ve seen his car twice going into Seven Gables on the Slough Road. I think he must have a friend there.” “Whose car?” asked the startled Elk. “It may be his or his friend’s car,” said the nurse. “Is he a friend of yours?” “He is in a way,” said Elk cautiously. She stood for a moment thinking. “Will you come in, please?” He followed her into the clean and tidy little parlour. “I don’t know why I told you, or why I’ve been talking so freely to you,” she said, “but the truth is, I’ve given Mr. Balder notice. He makes so many complaints, and he’s so difficult to please, that I can’t satisfy him. It isn’t as though he paid me a lot of money—he doesn’t. I make very little profit out of his rooms, and I’ve a chance of letting them at a better rent. And then he’s so particular about his letters. I’ve had a letter-box put on the door, but even that is not big enough to hold them some days. What his other business is, I don’t know. The letters that come here are for the Didcot Chemical Works. You probably think that I am a very difficult woman to please, because, after all, he’s out all day and seldom sleeps here at night.” Elk drew a long breath. “I think you’re nearly the finest woman I’ve ever met,” he said. “Are you going out now?” She nodded. “I’ve an all night case, and I shan’t be back till eleven to-morrow. You were very fortunate in finding anybody at home.” “I think you said ‘his car’; what sort of a car is it?” asked Elk. “It’s a black machine—I don’t know the make; I think it is an American make. And he must have something to do with the ownership because once I found a lot of tyre catalogues in his bedroom, and some of the tyres he had marked with a pencil, so I suppose he’s responsible to an extent.” One last question Elk asked. “Does he come back here at night after you’ve gone?” “Very rarely, I imagine,” replied the woman. “He has his own key, and as I’m very often out at night I’m not sure whether he returns or not.” Elk stood with one foot on the running-board of his car. “Perhaps I can drop you somewhere, madam?” he said, and the elderly woman gratefully accepted. Elk went back to headquarters, opened a drawer of his desk and took out a few implements of his profession, and, after filing a number of urgent instructions, returned to the waiting car, driving to Harley Terrace. Dick Gordon had an engagement that night to join a theatre party with the members of the American Embassy, and he was in one of the boxes at the Hilarity Theatre when Elk opened the door quietly, tapped him on the shoulder, and brought him out into the corridor, without the remainder of the party being aware that their guest had retired. “Anything wrong, Elk?” asked Gordon.