“Why do they think that?  What reason can they have for such a conclusion?  Was she seen?”

“Her footprints were plainly visible, and the revolver used was a small one—­a ’36’—­such as a woman alone would carry in this country.  I have said so to no one else, but I saw her, crouching in the shadow of the barrack wall.”

“You—­you saw her?  Recognized her?”

“Yes.”

“And made no attempt at arrest?  Have not even mentioned the fact to others?  You must have a reason?”

“I have, Mrs. Dupont, but we will not discuss it now.  I merely wish you to comprehend that if it is to be war between us, I am in possession of weapons.”

She had not lost control of herself, yet there was that about her hesitancy of speech, her quick breathing, which evidenced her surprise at this discovery.  It told him that he had played a good hand, had found a point of weakness in her armor.  The mystery of it remained unsolved, but this woman knew who had shot Gaskins; knew, and had every reason to guard the secret.  He felt her eyes anxiously searching his face, and laughed a little bitterly.

“You perceive, madam,” he went on, encouraged by her silence, “I am not now exactly the same unsuspecting youth with whom you played so easily years ago.  I have learned some of life’s lessons since; among them how to fight fire with fire.  It is a trick of the plains.  Do you still consider it necessary for your happiness to remain the guest of the McDonalds?”

She straightened up, turning her eyes away.

“Probably not for long, but it is no threat of yours which influences me.  It does not even interest me to know who shot Lieutenant Gaskins.  He is a vulgar little prig, only made possible by the possession of money.  However, when I decide to depart, I shall probably do so without consulting your pleasure.”  She hesitated, her voice softening as though in change of mood.  “Yet I should prefer parting with you in friendship.  In asking you to meet me to-night I had no intention of quarrelling; merely yielded to an impulse of regret for the past—­”

The heavy curtain draping the window was drawn aside, permitting the light from within to flash upon them, revealing the figure of a man in uniform.

“Pardon my interruption,” he explained, bowing, “but you were gone so long, Mrs. Dupont, I feared some accident.”

She laughed lightly.

“You are very excusable.  No doubt I have been here longer than I supposed.”

The officer’s eyes surveyed the soldier standing erect, his hand lifted in salute.  The situation puzzled him.

“Sergeant Hamlin, how are you here?  On leave?”

“Yes, sir.”

“Of course this is rather unusual, Captain Barrett,” said the lady hastily, tapping the astonished officer lightly with her fan, “but I was once quite well acquainted with Sergeant Hamlin when he was a major of the Fourth Texas Infantry during the late war.  He and my husband were intimates.  Naturally I was delighted to meet with him again.”