The stranger never took his eyes off the pair.  The man was slightly taller than the woman, and the latter wore upon her white kid shoes a pair of old paste buckles.  It was for those buckles that he had been searching.

“Yes,” he muttered in English beneath his breath.  “That’s she—­without a doubt!”

He drew back to near where the pair had halted and were laughing together.  The girl with the glittering buckles upon her shoes was Dorise Ranscomb.  The man with her was the Count d’Autun.

The white cavalier pretended to take no interest in them, but was, nevertheless, watching intently.  At last he saw the girl’s partner bow, and leaving her, he crossed to greet a stout Frenchwoman in a plain domino.  In a moment the cavalier was at the girl’s side.

“Please do not betray surprise, Miss Ranscomb,” he said in a low, refined voice.  “We may be watched.  But I have a message for you.”

“For me?” she asked, peering through her mask at the man in the plumed hat.

“Yes.  But I cannot speak to you here.  It is too public.  Besides, your mother yonder may notice us.”

“Who are you?” asked the girl, naturally curious.

“Do not let us talk here.  See, right over yonder in the corner behind where they are dancing in a ring—­under the balcony.  Let us meet there at once. Au revoir.”

And he left her.

Three minutes later they met again out of sight of Lady Ranscomb, who was still sitting at one of the little wicker tables talking to three other women.

“Tell me, who are you?” Dorise inquired.

The white cavalier laughed.

“I’m Mr. X,” was his reply.

“Mr. X?  Who’s that?”

“Myself.  But my name matters nothing, Miss Ranscomb,” he said.  “I have come here to give you a confidential message.”

“Why confidential—­and from whom?” she asked, standing against the wall and surveying the mysterious masker.

“From a gentleman friend of yours—­Mr. Henfrey.”

“From Hugh?” she gasped.  “Do you know him?”

“Yes.”

“I expected him to come with us to-night, but he has vanished from his hotel.”

“I know.  That is why I am here,” was the reply.

There was a note in the stranger’s voice which struck her as somehow familiar, but she failed to recognize the individual.  She was as quick at remembering voices as she was at recollecting faces.  Who could he be, she wondered?

“You said you had a message for me,” she remarked.

“Yes,” he replied.  “I am here to tell you that a serious contretemps has occurred, and that Mr. Henfrey has escaped from France.”

“Escaped!” she echoed.  “Why?”

“Because the police suspect him of a crime.”

“Crime!  What crime?  Surely he is innocent?” she cried.

“He certainly is.  His friends know that.  Therefore, Miss Ranscomb, I beg of you to betray no undue anxiety even if you do not hear from him for many weeks.”