“Faith, man!” she said impatiently, “you must seek for another opportunity then. I am going to Lord Grenville’s ball to-night after the opera. So are you, probably. I’ll give you five minutes then….”

“Three minutes in the privacy of this box are quite sufficient for me,” he rejoined placidly, “and I think that you will be wise to listen to me, Citoyenne St. Just.”

Marguerite instinctively shivered. Chauvelin had not raised his voice above a whisper; he was now quietly taking a pinch of snuff, yet there was something in his attitude, something in those pale, foxy eyes, which seemed to freeze the blood in her veins, as would the sight of some deadly hitherto unguessed peril.

“Is that a threat, citoyen?” she asked at last.

“Nay, fair lady,” he said gallantly, “only an arrow shot into the air.”

He paused a moment, like a cat which sees a mouse running heedlessly by, ready to spring, yet waiting with that feline sense of enjoyment of mischief about to be done. Then he said quietly—

“Your brother, St. Just, is in peril.”

Not a muscle moved in the beautiful face before him. He could only see it in profile, for Marguerite seemed to be watching the stage intently, but Chauvelin was a keen observer; he noticed the sudden rigidity of the eyes, the hardening of the mouth, the sharp, almost paralysed tension of the beautiful, graceful figure.

“Lud, then,” she said, with affected merriment, “since ’tis one of your imaginary plots, you’d best go back to your own seat and leave me to enjoy the music.”

And with her hand she began to beat time nervously against the cushion of the box. Selina Storace was singing the “Che faro” to an audience that hung spellbound upon the prima donna’s lips. Chauvelin did not move from his seat; he quietly watched that tiny nervous hand, the only indication that his shaft had indeed struck home.

“Well?” she said suddenly and irrelevantly, and with the same feigned unconcern.

“Well, citoyenne?” he rejoined placidly.

“About my brother?”

“I have news of him for you which, I think, will interest you, but first let me explain…. May I?”

The question was unnecessary. He felt, though Marguerite still held her head steadily averted from him, that her every nerve was strained to hear what he had to say.

“The other day, citoyenne,” he said, “I asked for your help…. France needed it, and I thought I could rely on you, but you gave me your answer…. Since then the exigencies of my own affairs and your own social duties have kept us apart … although many things have happened….”

“To the point, I pray you, citoyen,” she said lightly; “the music is entrancing, and the audience will get impatient of your talk.”

“One moment, citoyenne. The day on which I had the honor of meeting you at Dover, and less than an hour after I had your final answer, I obtained possession of some papers, which revealed another of those subtle schemes for the escape of a batch of French aristocrats—that traitor de Tournay amongst others—all organized by that arch-meddler, the Scarlet Pimpernel. Some of the threads, too, of this mysterious organization have fallen into my hands, but not all, and I want you—nay! you must help me to gather them together.”