"But he comes alone. That is the little thing I cannot explain. Where is Betty Harlowe? I ask for her before I go into the treasure-room, and lo! very modestly and quietly she has slipped in amongst us again. I am very curious about that, my friend, and I keep my eyes open for an explanation, I assure you."
"I remember," said Frobisher. "You stopped with your hand upon the door and asked for Mademoiselle Harlowe. I wondered why you stopped. I attached no importance to her absence."
Hanaud flourished his hand. He was happy. He was in the artist's mood. The work was over, the long strain and pain of it. Now let those outside admire!
"Of all that the treasure-room had to tell us, you know, Monsieur Frobisher. But I answer a question in your memorandum. The instant I am in the room, I look for the mouth of that secret passage from the Hôtel de Brebizart. At once I see. There is only one place. The elegant Sedan chair framed so prettily in a recess of the wall. So I am very careful not to pry amongst its cushions for the poison arrow; just as I am very careful not to ask for the envelope with the post mark in which the anonymous letter was sent. If Betty Harlowe thinks that she has overreached the old fox Hanaud—good! Let her think so. So we go upstairs and I find the explanation of that little matter of Betty Harlowe's absence which has been so troubling me."
Jim Frobisher stared at him.
"No," he said. "I haven't got that. We went into Ann Upcott's sitting-room. I write my memorandum with the shaft of the poison arrow and you notice it Yes! But the matter of Betty Harlowe's absence! No, I haven't got that."
"But you have," cried Hanaud. "That pen! It was not there in the pen-tray on the day before, when I found the book. There was just one pen—the foolish thing young ladies use, a great goose-quill dyed red—and nothing else. The arrow shaft had been placed there since. When? Why, just now. It is clear, that. Where was that shaft of the poison-arrow before? In one of two places. Either in the treasure-room or in the Hôtel de Brebizart. Betty Harlowe has fetched it away during that hour of freedom; she carries it in her dress; she seizes her moment when we are all in Madame Harlowe's bedroom and—pau, pau!—there it is in the pen-tray of Mademoiselle Ann, to make suspicion still more convincing! Monsieur, I walk away with Monsieur Bex, who has some admirable scheme that I should search the gutters for a match-box full of pearls. I agree—oh yes, that is the only way. Monsieur Bex has found it! On the other hand I get some useful information about the Maison Crenelle and the Hôtel de Brebizart. I carry that information to a very erudite gentleman in the Palace of the Departmental Archives, and the next morning I know all about the severe Etienne de Crenelle and the joyous Madame de Brebizart. So when you and Betty Harlowe are rehearsing in the Val Terzon, Nicolas Moreau and I are very busy in the Hôtel de Brebizart—with the results which now are clear to you, and one of which I have not told you. For the pearl necklace was in the drawer of the writing-table."
Jim Frobisher took a turn across the terrace. Yes, the story was clear to him now—a story of dark passions and vanity, and greed of power with cruelties for its methods. Was there no spark of hope and cheer in all this desolation? He turned abruptly upon Hanaud. He wished to know the last hidden detail.
"You said that you had made the inexcusable mistake. What was it?"
"I bade you read my estimate of Ann Upcott on the façade of the Church of Notre Dame."