“He’s following someone. Yesterday he was out as a workman looking for a job. Today he was an old woman. Fairly took me in, he did, and I ought to know his ways by now.” Billy pointed with a grin to a very baggy parasol which leaned against the sofa. “That’s part of the old woman’s outfit,” he said.

“But what is it all about, Billy?”

Billy sank his voice, as one who discusses great secrets of State. “I don’t mind telling you, sir, but it should go no farther. It’s this case of the Crown diamond.”

“What⁠—the hundred-thousand-pound burglary?”

“Yes, sir. They must get it back, sir. Why, we had the Prime Minister and the Home Secretary both sitting on that very sofa. Mr. Holmes was very nice to them. He soon put them at their ease and promised he would do all he could. Then there is Lord Cantlemere⁠—”

“Ah!”