So far as Jack could discern, his companion appeared to be equally disconcerted. But there would be plenty of time presently to learn what Nostalgo knew about Serena. Events were moving rapidly now, and Jack felt that he would have plenty to tell Rigby later on. They stood aside till Serena had left the house, making sure that the latch was down, and that no one could enter the premises without a key. Jack turned to Nostalgo with an interrogative glance.

"The more we go into this thing," he said, "the more do we find one mystery piled upon another. Do you know that unfortunate lady?"

"If you do not mind, I would much rather you did not press that question," Nostalgo said, coldly. "I am going to help you all I can; I am going to do everything in my power both for your sake and mine; but there are some things which will not bear discussion, and this is one of them."

Jack turned away, feeling just a little hurt and disappointed. He would have found it difficult to say why, but he had taken a strange liking to the man by his side, perhaps because the man was suffering more from terrible misfortune than from his own imprudence.

"We will let it stand over for the present," he said, "but to be more candid than you are, I am greatly interested in that poor woman. I have known her for a long time now, and, as a novelist, I am bound to say that she greatly fascinates me. She always strikes me as a woman who has been tamed--she is so like a performing lion or tiger, if you will permit me the simile."

"I think I know what you mean," Nostalgo said. "The class of animal you speak of paces restlessly about its cage, a picture of moody discontent and more or less physical fear. And then the time comes when all the old savage instincts burst forth, and years of cruel treatment are avenged in the course of a moment."

"And so it would be with Serena," Jack said. "I have seen her cower and tremble before her master; I have seen her hand him a knife in the humblest possible fashion. And then I have seen her hands clench on the handle, and a gleam come into her eyes--on more than one occasion I have half expected to see her lean over and cut her master's throat from ear to ear. After this, perhaps, you may be disposed to say more on the subject?"

"We have never met, we have never been introduced," Nostalgo explained; "but I know who she is and all about her just the same. Do not press me more at present; the secret is not entirely my own. I can only tell you this: it was a great shock to me to meet that unfortunate lady to-night. But perhaps you know who she is?"

"I know perfectly well who she is," Jack said, "though the knowledge has come to me quite recently. Up to a day or two ago I regarded her in the prosaic light of Anstruther's housekeeper. She has always interested me, because she has always seemed to me to be a kind of wild animal who has been cleverly tamed. I have seen her like a tiger ready to spring; I have seen the lurking demon of passion in her eyes, as if she could destroy Anstruther and rejoice in the deed. And then a word from him or a glance, and she has cowered as timidly as the wife of the veriest bully in the world."

"But that isn't telling me who she is," Nostalgo said, impatiently.