"Stop, stop!" cried Mona, running to the door, through which he had so promptly vanished; and the others following, echoed her urgent cry. But by the time they reached the hall the door was wide open, and Horace had disappeared as completely as though the earth had swallowed him up. Beyond was the darkness, which veiled him. "Is he mad?" asked Mona, turning an amazed face to the three men. "Mad or not, he has done you a service," said Martaban, looking down at the will, which he still held. "This is undoubtedly your uncle's last testament, which was _not_ burnt. It is signed by Sir Oliver in the presence of Stephen Agstone and Emma Blexey. What a facer this will be for our South Sea friend," ended the lawyer, actually becoming slangy in his delight. "Ought we to follow Horace?" Shepworth asked. "No," replied Prelice, who was frowning at Horace's manners; "even if we caught up with him, he would say nothing. We must wait to see if he will again intervene in the case." "He seems to have washed his hands of it," said Ned, sauntering back to the drawing-room. "He did so before, yet when Miss Chent wired he came down. I wonder----" Prelice paused, and bit his fingers. "You wonder what?" "If Horace killed Sir Oliver and Agstone." Shepworth stared. "That's a rotten bad shot, Dorry. Why should he?" "Oh, I can assign no reason, but----" "My dear old chap, it is absurd. I know you are thinking of the will being brought here by Horace; but why should not his story be a true one, since Agstone is his brother?" "Well," Prelice threw out his hands with a despairing gesture, "I can't understand the whole business; it passes my powers of comprehension." Before Ned could reply Mona summoned both the young men. Along with Martaban, she had been opening the parcel which Horace had thrown across the room, and was now exclaiming at its contents. "Ned, Lord Prelice, here is the Sacred Herb." They hurried over to have a look, and there sure enough was the yellowish stalk of the herb from Easter Island, bearing seven or more purple leaves. In addition, there was a written paper, which Mona read aloud. "Use the enclosed when Jadby comes to close quarters and makes himself unpleasant," she read in a bewildered manner; "also, it will be as well for you to use your power over Lord Prelice to prevent his searching further in this case. If he meddles with what does not concern him, it means sorrow, and perhaps a public scandal." There was a dead silence. "Now what does that mean?" asked Mona. No one knew; no one dared to suggest an explanation. Prelice was the first to speak. "I advise you, Miss Chent, to obey Horace, and keep this herb constantly in your pocket. He is not the man to give a warning without some grave reason. He has saved you once from Jadby, and this herb, as he plainly says, intimates that it will save you again." "But why should----"