Morton's anxious
eyes. "I can never repay you for your kindness--never. But if you can
save Ruth from these scoundrels, I will gladly spend----"

"Never mind about that, Mrs. Morton," Duvall observed, with a friendly
smile. "It is scarcely a question of money with me. If I had not felt a
keen interest in your daughter's welfare, I should not have agreed to
take up the matter at all. As it is, you need not worry about the
expense. I am going to take the case largely because it has interested
me, and it will be a pleasure to work it out, not only on your
daughter's account, but on my own. You know, to me, such matters are of
absorbing interest, like the solving of some complex and baffling
puzzle."

"Then you will go back to New York with me this evening?"

"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
charac