At his command she consented to pass as his sister, though he found the limits of his power over her when he endeavoured to make her the direct accessory to murder. She was ready to warn Sir Henry so far as she could without implicating her husband, and again and again she tried to do so. Stapleton himself seems to have been capable of jealousy, and when he saw the baronet paying court to the lady, even though it was part of his own plan, still he could not help interrupting with a passionate outburst which revealed the fiery soul which his self-contained manner so cleverly concealed. By encouraging the intimacy he made it certain that Sir Henry would frequently come to Merripit House and that he would sooner or later get the opportunity which he desired. On the day of the crisis, however, his wife turned suddenly against him. She had learned something of the death of the convict, and she knew that the hound was being kept in the out-house on the evening that Sir Henry was coming to dinner. She taxed her husband with his intended crime, and a furious scene followed, in which he showed her for the first time that she had a rival in his love. Her fidelity turned in an instant to bitter hatred and he saw that she would betray him. He tied her up, therefore, that she might have no chance of warning Sir Henry, and he hoped, no doubt, that when the whole country-side put down the baronet's death to the curse of his family, as they certainly would do, he could win his wife back to accept an accomplished fact and to keep silent upon what she knew. In this I fancy that in any case he made a miscalculation, and that, if we had not been there, his doom would none the less have been sealed. A woman of Spanish blood does not condone such an injury so lightly. And now, my dear Watson, without referring to my notes, I cannot give you a more detailed account of this curious case. I do not know that anything essential has been left unexplained."
"He could not hope to frighten Sir Henry to death as he had done the old uncle with his bogie hound."
"The beast was savage and half-starved. If its appearance did not frighten its victim to death, at least it would paralyze the resistance which might be offered."
"No doubt. There only remains one difficulty. If Stapleton came into the succession, how could he explain the fact that he, the heir, had been living unannounced under another name so close to the property? How could he claim it without causing suspicion and inquiry?"
"It is a formidable difficulty, and I fear that you ask too much when you expect me to solve it. The past and the present are within the field of my inquiry, but what a man may do in the future is a hard question to answer. Mrs. Stapleton has heard her husband discuss the problem on several occasions. There were three possible courses. He might claim the property from South America, establish his identity before the British authorities there and so obtain the fortune without ever coming to England at all; or he might adopt an elaborate disguise during the short time that he need be in London; or, again, he might furnish an accomplice with the proofs and papers, putting him in as heir, and retaining a claim upon some proportion of his income. We cannot doubt from what we know of him that he would have found some way out of the difficulty. And now, my dear Watson, we have had some weeks of severe work, and for one evening, I think, we may turn our thoughts into more pleasant channels. I have a box for 'Les Huguenots.' Have you heard the De Reszkes? Might I trouble you then to be ready in half an hour, and we can stop at Marcini's for a little dinner on the way?"