Irene sat silent, trapped.

“This is why I have come to you,” continued Agatha, very seriously.  “I am employed by those whose identity I must not disclose to sift this mystery of Colonel Weatherby to the bottom, if possible, and then to fix the guilt where it belongs.  By accident you have come into possession of certain facts that would be important in unravelling the tangle, but through your unfortunate affliction you are helpless to act in your own capacity.  You need an ally with more strength and experience than yourself, and I propose you accept me as that ally.  Together we may be able to clear the name of James J. Hathaway—­who now calls himself Colonel James Weatherby—­from all reproach and so restore him to the esteem of his fellow men.”

“But we must not do that, even if we could!” cried Irene, quite distressed by the suggestion.

“Why not, my dear?”

The tone was so soft and cat-like that it alarmed Irene instantly.  Before answering she took time to reflect.  To her dismay she found this woman was gradually drawing from her the very information she had declared she would preserve secret.  She knew well that she was no match for Agatha Lord in a trial of wits.  Her only recourse must be a stubborn refusal to explain anything more.

“Colonel Weatherby,” she said slowly, “has better information than I of the charge against him and his reasons for keeping hidden, yet he steadfastly refuses to proclaim his innocence or to prove he is unjustly accused, which he might very well do if he chose.  You say you are working in his interests, and, allowing that, I am satisfied he would bitterly reproach anyone who succeeded in clearing his name by disclosing the truth.”

This argument positively amazed Agatha Lord, as it might well amaze anyone who had not read the letter.  In spite of her supreme confidence of the moment before, the woman now suddenly realized that this promising interview was destined to end disastrously to her plans.

“I am so obtuse that you will have to explain that statement,” she said with assumed carelessness; but Irene was now on guard and replied: 

“Then our alliance is dissolved.  I do not intend, Miss Lord, to betray such information as I may have stumbled upon unwittingly.  You express interest in Mary Louise and her grandfather and say you are anxious to serve them.  So am I. Therefore I beg you, in their interests, to abandon any further attempt to penetrate the secret.”

Agatha was disconcerted.

“Show me the letter,” she urged, as a last resort.  “If, on reading it, I find your position is justifiable—­you must admit it is now bewildering--I will agree to abandon the investigation altogether.”

“I will not show you the letter,” declared the girl positively.

The woman studied her face.

“But you will consider this conversation confidential, will you not?”

“Since you request it, yes.”