"I can hardly do that, Mrs. Morton. But I can agree to call on you there to-morrow. It will take me some hours to arrange matters here so that I can leave. I do not think you need worry for a few days at least. If these people had meant to act at once they would not have named the period of thirty days in their threats." "Very well." Mrs. Morton rose, and held out her hand. "I will expect you to-morrow. Will it be in the morning?" "Very likely. In any event, I will first telephone to you." He entered the address in his notebook. "By the way, perhaps you had better let me keep that photograph." "Certainly." Mrs. Morton handed it to him, and he thrust it into his pocket. "The letters you already have?" "Yes." "Is there anything else?" "Yes. One thing. Do not tell your daughter that you have employed me in this case. It--it might alarm her." "Certainly not. And that leads me to say that you, on your part, will of course observe the utmost secrecy. Even with Mrs. Duvall." "That goes without saying, madam. My professional secrets I share with no one. Even between my wife and myself there is an unwritten law which is never broken. Unless we are working on a case together--unless she can be of service to me, she asks no questions. She would not speak to me, or even recognize me, were we to meet, while I am engaged in work of this sort. You need have no fear on that score." "I am very glad to know that. Were these people to suspect that I have placed the matter in the hands of a detective, they would be instantly on their guard, and all means of tracing them might be lost." "That is undoubtedly true, and for that reason, I may appear in other characters than my own, from time to time, disguised perhaps, in such a way that even you would not recognize me. Under those circumstances I will suggest a password--one that will not be known to anyone else. Should occasion arise in which I desire to acquaint you with my identity, without making it known to others, I will merely repeat the words--twenty-eight days, or twenty-seven or six or five, as the case may be, on that particular day, and you will know that it is I, and act accordingly. Is that perfectly clear?" "Perfectly, Mr. Duvall." "Very well. Then we will leave further details until to-morrow." He shook hands with his caller, escorted her to her automobile, then returned to the library and began a careful study of the two notes which Mrs. Morton had left with him. Here Grace found him, half an hour later. "Well," she said, coming up to him with a smile. "Shall I begin to pack our things?" Duvall put his arm about her. "Yes, dear," he said. "We'll leave on the sleeper to-night. You can get Mrs. Preston to come and take charge of the house while we are gone. It may be two weeks. That is, if you want to go along."