“That,” continued Llewellyn, well launched now on a subject close to his heart, “is supposed to have been worn by the Black Prince at the Battle of Creçy. That is a second thing that I should have missed instantly.” Inspector Goodall cut in. “Let’s put it like this, Mr. Llewellyn, or you, Mr. Stewart! Do either of you miss anything at all—that’s the quickest way to get to grips with the question?” Llewellyn made a tour of the room. “I miss nothing, Inspector.” Charles Stewart shook his head rather despondently. “I can’t help you and that’s a fact, Inspector. You must leave it at that.” He looked at Anthony Bathurst, who was, however, busy at the moment turning over the leaves of Llewellyn’s catalogue. “Well then, if that’s the case,” rejoined Goodall, “no particularly good purpose will be served by us stopping in here any longer. I’m afraid Mr. Bathurst has given us a ‘stunner’ this time.” “Half a minute,” interposed Anthony quietly. “You’ve all had an innings, now it’s my turn. Listen to me for two minutes. Mr. Llewellyn”—he turned to the secretary—“consider for a moment item number eight hundred and sixty-six in the catalogue, will you?” Apparently the number conveyed nothing to Llewellyn, for his face was unchanged. “Eight—six—six?” he inquired. “I’ll read you the description I find here,” proceeded Anthony. “Antique fire-screen, of beaten metal-work—about four feet high. Originally the property of Mary, Queen of Scots.” He tucked the catalogue under his arm. “I’d like to have a look at that,” he said, “I’m interested.” Llewellyn raised his forefinger. “You shall, Mr. Bathurst, I do know it now you mention it—it’s in this corner—behind this collection of Waterford glass.” He crossed to the right-hand corner of the room. Anthony scratched the back of his neck—watching Llewellyn pick his way between the tables. Suddenly the secretary stopped, and although his back was towards them, more than one of the four detected an anxiety in the manner of his stopping. Then he turned—his face white and working with excitement. “It’s gone, gentlemen,” he cried. “It’s not here—come and look yourself, Mr. Stewart.” Charles Stewart walked quickly to the corner. “There’s no screen here,” he declared. “Mightn’t it be somewhere else?” asked the Inspector. “Are these things always kept in precisely the same spot?” “Always, Inspector,” replied Morgan Llewellyn promptly. “Mr. Stewart was most particular about that.” “Isn’t it possible that Mr. Stewart himself may have removed it—on the eve of his intended purchases—for comparison or something?” suggested Daventry. “No,” said Llewellyn. “I think not. I’m certain Mr. Stewart would have told me if he had done so.” “Goodall,” said Anthony, with a suspicion of the didactic in his manner, “I can now assure you of at least one thing! Mason, the night-watchman, was murdered for possession of the other Stuart screen!” “And my father——” broke in Charles Stewart with emotion.