“I’ve often wondered,” ruminated Elk, “what people like you do their thinking with.” “Now look here——!” began the lift-man indignantly. “Look here,” retorted Elk, and at the sight of his badge the man grew more polite and more informative. “She’s been here two months,” he said. “And, to tell you the truth, Mr. Elk, I’ve often wondered how she got a suite in Caverley House. They tell me she used to run a gambling joint on Jermyn Street. You haven’t come to raid her, have you?” he asked anxiously. “That’d get Caverley House a pretty bad name.” “I’ve come to make a friendly call,” said Elk carefully. “That’s the door.” The man stepped out of the lift and pointed to one of the two sober mahogany doors on the landing. “This other flat belongs to an American millionaire.” “Is there such a thing?” asked Elk. He was about to say something more when the lift-man walked to the door and peered at one of its polished panels. “That’s queer,” he said. “What do you make of this?” Elk joined him, and at a glance saw and understood. On the panel had been stamped a small white frog—an exact replica of those he had seen that morning on the photographs that Dick Gordon had shown him. A squatting frog, slightly askew. He touched it. The ink was still wet and showed on his finger. And then the strangest thing of all happened. The door opened suddenly, and a man of middle age appeared in the doorway. In his hand was a long-barrelled Browning, and it covered the detective’s heart. “Put up your hands!” he said sharply. Then he stopped and stared at the detective. Elk returned the gaze, speechless; for the elegantly dressed man who stood there was the hawk-faced pedlar he had seen in Whitehall! The American was the first to recover. Not a muscle of his face moved, but Elk saw again that light of amusement in his eyes as he stepped back and opened the door still wider. “Come right in, Mr. Elk,” he said, and, to the amazed lift-man; “It’s all right, Worth. I was practising a little joke on Mr. Elk.” He closed the door behind him, and with a gesture beckoned the detective into a prettily furnished drawing-room. Elk went in, leaving the matter of the frog on the door for discussion later. “We’re quite alone, Mr. Elk, so you needn’t lower your voice when you talk of my indiscretions. Will you smoke a cigar?” Elk stretched out his fingers mechanically and selected a big Cabana. “Unless I’m greatly mistaken, I saw you this morning,” he began. “You weren’t mistaken at all,” interrupted the other coolly. “You saw me on Whitehall. I was peddling key-rings. My name is Joshua Broad. You haven’t anything on me for trading in a false name.” The detective lit his cigar before he spoke. “This apartment must cost you a whole lot to keep up,” he said slowly, “and I don’t blame you for trying to earn something on the side. But it seems to me that peddling key-rings is a very poor proposition for a first-class business man.” Joshua Broad nodded.