So I discovered that the box had sat overnight in the Benton house.  There remained, if I was to help Miss Emily, to discover what had occurred in those dark hours when the books were taken out and something else substituted.

The total result of my conversation that afternoon on the front porch of the small frame house on a side street with the night telephone-operator was additional mystery.

I was not prepared for it.  I had anticipated resentment and possibly insolence.  But I had not expected to find fright.  Yet the girl was undeniably frightened.  I had hardly told her the object of my visit before I realized that she was in a state of almost panic.

“You can understand how I feel,” I said.  “I have no desire to report the matter, of course.  But some one has been calling the house repeatedly at night, listening until I reply, and then hanging up the receiver.  It is not accidental.  It has happened too often.”

“I’m not supposed to give out information about calls.”

“But—­just think a moment,” I went on.  “Suppose some one is planning to rob the house, and using this method of finding out if we are there or not?”

“I don’t remember anything about the calls you are talking about,” she parried, without looking at me.  “As busy as I am—­”

“Nonsense,” I put in, “you know perfectly well what I am talking about.  How do I know but that it is the intention of some one to lure me downstairs to the telephone and then murder me?”

“I am sure it is not that,” she said.  For almost the first time she looked directly at me, and I caught a flash of something—­not defiance.  It was, indeed, rather like reassurance.

“You see, you know it is not that.”  I felt all at once that she did know who was calling me at night, and why.  And, moreover, that she would not tell.  If, as I suspected, it was Miss Emily, this girl must be to some extent in her confidence.

“But—­suppose for a moment that I think I know who is calling me?” I hesitated.  She was a pretty girl, with an amiable face, and more than a suggestion of good breeding and intelligence about her.  I made a quick resolve to appeal to her.  “My dear child,” I said, “I want so very much, if I can, to help some one who is in trouble.  But before I can help, I must know that I can help, and I must be sure it is necessary.  I wonder if you know what I am talking about?”

“Why don’t you go back to the city?” she said suddenly.  “Go away and forget all about us here.  That would help more than anything.”

“But—­would it?” I asked gently.  “Would my going away help—­her?”

To my absolute amazement she began to cry.  We had been sitting on a cheap porch seat, side by side, and she turned her back to me and put her head against the arm of the bench.

“She’s going to die!” she said shakily.  “She’s weaker every day.  She is slipping away, and no one does anything.”