I took a sudden resolve.  “I very much fear my unexpected presence to-night is a source of concern and inconvenience to Your Excellency,” I said.  “With your permission I will take my leave,” and I made to go.

Vierle came quickly to me.

“It will make the Marquise and me most unhappy, if you do,” he said.  “And I shall tell you frankly what brought me here.  The lady who styles herself your wife is among the guests—­she is in the next room, now, waiting to be admitted.  My purpose was to have the Marquise request her to depart at once.”

I laughed, and put my hand on his shoulder.

“So far as I am concerned,” I said, “I pray you do nothing of the sort.  The lady does not bother me in the slightest.  Besides, she will not know I’m here—­and I shall not present myself to her, you may be sure.”

“Yet, we owe Your Highness an explanation of her presence,” the Marquise exclaimed.

“My dear Madame de Vierle, you owe me nothing of the sort,” I said.  “I am still enough of an American to think that a hostess is never called upon to explain a guest.  And, what is more, the whole difficulty is of my own making, in coming after I had declined.”

“Surely, Your Highness is very gracious; yet, I would very much prefer to explain,” she said.  “It was this way:  Madeline Stafford and I were friends and schoolmates in Paris.  We both married about the same time and, then, lost touch with each other.  I had neither seen nor heard from her until I received a note some weeks ago.  After Your Highness regretted for to-night, I sent her a card.  I mentioned the matter to the Duke of Lotzen and he said that, under the circumstances, and as everyone would be masked, it would be entirely proper.  That is my explanation.”

“And one amply sufficient; even if any were required,” I said.

I thought I saw my dear cousin’s game.

“And you are quite sure you do not object to her remaining?”

“Quite sure,” said I; “and I even hope she will enjoy herself.  I shall, I know.  And, at supper, I’ll confide my adventures to your Ladyship.”  Then I took a shot in the dark.  “And I know His Highness of Lotzen will be forever sorry he could not be here to-night,” I added.

“He was good enough to call and tell me so,” was the answer.

I was sure, now, I saw my dear cousin’s game.

Then I bowed over the Marquise’s hand and Moore and I went out through the sliding door—­which, when the Marquis rolled it back for us, I saw was not locked.  In my haste I had not seen the small brass button which released the latch.

“It’s a pity Vierle didn’t tell us what costume Mrs. Spencer is wearing,” Moore remarked, as we reached the Garden.

I stopped short.  “What a blunderer I am.  It would be better if you did the thinking for me.”

“Shall I go back and ask him?”

“It will keep until supper,” said I.  “In the meantime, let us hunt up Courtney and Lady Helen.”  I explained to him how to distinguish them; then, taking from my doublet a small package wrapped in foil, I selected a red rose and put it in my mouth.