It was one night at the opera that the climax was brought about.  I sat in one of the stalls diagonally across from the royal box, where she sat.  She saw me and gave me the barest nod of recognition.  Perhaps she did not wish to attract the attention of the royal personages who sat with her; for the nod struck me as clandestine.  Between the first and second acts a note was handed to me.  It was not addressed, neither was it signed.  But it was for me; the bearer spoke my name.  As near as I can remember, the note contained these words: 

“A carriage will await you two blocks south; it will be without lights.  You will enter it exactly ten minutes after the opera is ended.”

That was all, but it was enough.  When I returned to my seat I found the Princess gazing intently at me.  I made an affirmative gesture and was rewarded with a smile which set my blood to rushing.  I made little out of the last act.  I could not dream what the anonymous note had behind it.  I suspicioned an intrigue, but what use had she for me, an American, a very nobody?  Something unusual was about to take place and I was to be a witness or a participant of it.  That was as far as my talent for logical deduction went.  Promptly at the stated time I stood at the side of the carriage.  It was the plainest sort of an affair.  Evidently it had been hired for the occasion.  The door opened.

“Step in, monsieur,” said a low voice in French.  I obeyed.  The horse started.  As we spun along the pavement a light flashed into the window.  The Princess sat before me.  There was a ringing in my ears, and I breathed quickly.  But I said no word; it was for her to speak first.

“Monsieur is an American,” she began.  “The American is of a chivalric race.”

“That should be the aim of all men,” I replied.

“But it is not so.  Monsieur, I have been studying you for the past week.  To-night I place my honor and my fame in your hands; it is for you to prove that you are a knight.  I trust you.  When I have said what I shall say to you, you may withdraw or give me your aid, as you please.”

“I am grateful for your confidence, your Highness,” said I.  “What is it that you wish me to do?”

“Have patience, monsieur, till the ride is done,” she said.  “Do not speak again till I permit you.  I must think.”

The journey was accomplished in half an hour.

“It is here, monsieur, that we alight,” she said as the carriage stopped.

I was glad that her opera cloak was of dark material and that she wore a veil.

The building before which we stood was on the outskirts of the city.  Far away to my left I could see the flickering lights of the palaces; a yellowish haze hung over all.  Once within the building I noted with surprise the luxurious appointments.  Plainly it was no common inn, a resort for the middle and traveling classes; whether it was patronized by the nobility I could only surmise.