“It is necessary that you come to the embassy at once.”

There was no signature.  The handwriting was unmistakably that of a woman, and just as unmistakably strange to him.  He frowned a little as he stared at it wonderingly, then idly turned the card over.  There was no name on the reverse side—­only a crest.  Evidently the count recognized this, for his impassive face reflected surprise for an instant, and this was followed by a keen, bewildered interest.  Finally he arose, made his apologies, and left the room.  His automobile was at the door.

[Illustration:  The handwriting was unmistakably that of a woman.]

“To the embassy,” he directed the chauffeur.

And within five minutes he was there.  His secretary met him in the hall.

“The lady is waiting in your office,” he explained apologetically.  “I gave her your message, but she said she must see you and would write you a line herself.  I sent it.”

“Quite correct,” commented the ambassador.  “What name did she give?”

“None,” was the reply.  “She said none was necessary.”

The ambassador laid aside hat and coat and entered his office with a slightly puzzled expression on his face.  Standing before a window, gazing idly out into the light-spangled night, was a young woman, rather tall and severely gowned in some rich, glistening stuff which fell away sheerly from her splendid bare shoulders.  She turned and he found himself looking into a pair of clear, blue-gray eyes, frank enough and yet in their very frankness possessing an alluring, indefinable subtlety.  He would not have called her pretty, yet her smile, slight as it was, was singularly charming, and there radiated from her a something—­personality, perhaps—­which held his glance.  He bowed low, and closed the door.

“I am at your service, Madam,” he said in a tone of deep respect.  “Please pardon my delay in coming to you.”

“It is unfortunate that I didn’t write the first note,” she apologized graciously.  “It would at least have saved a little time.  You have the card?”

He produced it silently, crest down, and handed it to her.  She struck a match, lighted the card, and it crumbled up in her gloved hand.  The last tiny scrap found refuge in a silver tray, where she watched it burn to ashes, then she turned to the ambassador with a brilliant smile.  He was still standing.

“The dinner isn’t over yet?” she inquired.

“No, Madam, not for another hour, perhaps.”

“Then there’s no harm done,” she went on lightly.  “The dinner isn’t of any consequence, but I should like very much to attend the ball afterward.  Can you arrange it for me?”

“I don’t know just how I would proceed, Madam,” the ambassador objected diffidently.  “It would be rather unusual, difficult, I may say, and—­”

“But surely you can arrange it some way?” she interrupted demurely.  “The highest diplomatic representative of a great nation should not find it difficult to arrange so simple a matter as—­as this?” She was smiling.