"You will be surprised when I tell you," Grey murmured. "The intruder is no other than Arnold Rent."

An exclamation of genuine surprise broke from Tanza's lips.

"Is that really a fact?" he demanded. "But what brings him here? What has he come after?"

"Ah, that I can only conjecture. I don't think my theory is far wrong. Although Arnold Rent is the son of a rich woman, he has by no means the command of unlimited money. Mrs. Rent is rather simple in her ideas and inclined to be somewhat of a Puritan. She is quite capable of leaving her money elsewhere if she thinks her son will waste it. Therefore, it has been a necessity on Rent's part that his mother should be deceived as to his mode of life. To put it plainly, he is more or less afraid of her. And when a man lives in a smart set, and has no control over his expenditure, he is bound sooner or later to find himself in difficulties. That is the matter with Rent. He did not know which way to turn for money. He did not dare to go to his mother and ask her to set him on his feet again. Therefore he hits upon another plan. He makes violent love to Bark's sister Hortense with a view to securing her mistress's diamonds. At first I don't believe that Rent cared for Mrs. Charlock at all. What he meant to do was to get hold of her jewels, but when he came to know the woman intimately she fascinated him to such an extent that he lost his head. He was prepared to sacrifice everything for her sake. Witness that mad idea of his taking Mrs. Charlock to stay with his mother. I give the fellow credit for honesty in that respect. I believe his affection for Mrs. Charlock was absolutely pure and good—perhaps the only disinterested impulse he ever had in his life. Meanwhile, he had talked Hortense over and between them they laid hands upon Mrs. Charlock's jewels. You will ask what became of the jewels. They were hidden in a place of safety, so that they might be available when they were wanted."

"That sounds logical," Tanza said. "Is it part of the problem to find the jewels, or do you know where they are?"

"I know where they are," was the unexpected reply. "They are within a stone's throw of us."

The little Italian whistled softly.

"Oh," he said, "I shall have to hand my mantle over to you, I see. But hadn't we better secure the plunder while we have the chance? It would be folly to miss the opportunity."

"Oh, the gems are safe enough," Grey said, with a grim chuckle. "You can almost touch them with your hands. And yet they are as safe as the Crown Jewels in the Tower of London. Indeed, they are safer, seeing that an attempt on the National Regalia would only end in imprisonment, while a determined attack upon Mrs. Charlock's gems would end in sudden death. I won't gratify your curiosity yet. I have told you enough for the present, and the truth, too. The first hand that rests upon that jewel case will be the hand of a corpse in the twinkling of an eye. In a day or two, perhaps, it may be safe to rifle the hiding-place. But not yet, not yet."

Grey spoke with a thrill in his voice that had something of horror in it. Tanza had seen too many mysteries in his time to express anything in the way of incredulity. On the contrary, he nodded his head solemnly.