“On the other side of which, my lad, lies the secret of the murder of my cousin,” said Allerdyke grimly.  “Mind you that!  That’s what I’m after, Fullaway.  Damn all these jewels and things, in comparison with that!—­it’s that I’m after, I tell you again, and a thousand times again.  And I’m considering if I’m doing any good hanging round here after this singing woman when the probable sphere of action lies yonder away at Hull, eh?”

“The proper—­not probable—­sphere of action, my dear sir, is the supper-table to which we’re presently going,” answered Fullaway, with supreme assurance.  “What the singing woman, as you call her, can tell us will most likely make all the difference in the world to our investigations.  Remember the shoe-buckle!  Have it ready to exhibit when I lead up to it.  Then—­we shall see.”

The prima donna, back for her engagement at eleven o’clock, came in flushed and smiling—­the extraordinary warmth and fervour of her reception by the audience which she had at first been so inclined to treat with scant courtesy had restored her to good humour, and when she had eaten a few mouthfuls of delicate food and drunk her first glass of champagne she began to laugh almost light-heartedly.

“Well, I suppose you’ve been doing your best, Fullaway,” she said, with easy familiarity.  “I declare you turned up at the very moment, for that fat Weiss would have been no good.  But I’m still wondering how you came to be here, and what this gentleman—­Mr. Allerdyke, is it?—­is doing here with you.  Allerdyke, now—­well, that’s the same name as that of a man I came across from Christiania with, and left at Hull.”

Fullaway kicked Allerdyke under the table.

“You haven’t heard of that Mr. Allerdyke since you left him at Hull, then?” he asked, gazing intently at their hostess.

“Heard?  How should I hear?” asked the prima donna.  “He was just a travelling acquaintance.  All the same, I had certainly fixed up to see him in London on a business matter.”

“You don’t read the newspapers, then?” suggested Fullaway.

“Not unless there’s something about myself in them,” she answered, with an arch smile at Allerdyke.

“If you’d read this morning’s papers, you’d have seen that the Mr. Allerdyke with whom you travelled—­this gentleman’s cousin, by the by—­was found dead in his room at the hotel in Hull not so long after you quitted it,” said Fullaway coolly.  “In fact, he must have been dead when you passed his door on your way out.”

The prima donna was genuinely shocked.  She set down the glass which she was just lifting to her lips; her large, handsome eyes dilated, her lips quivered a little.  She turned a look of sympathy on Allerdyke, who, at that moment, realized that she was a very beautiful woman.

“You don’t say so!” she exclaimed.  “Well, I’m really grieved to hear that—­I am!  Dead?—­and when I left!  Why, I was in his room that very night we reached Hull, having a talk on the business matter I mentioned just now—­he was well enough and lively enough then, I’ll swear.  Dead!—­why, what did he die of?”