The words suddenly froze on her lips. Wilfrid, gazing upon her face, saw its loveliness distorted by a terrible change. With blanched cheek and open mouth she was staring at something or somebody behind him. Her strange set expression almost suggested the wild fancy that there had risen from out the foliage the head of Medusa, whose chilling stare could turn the beholder to stone. Something of her feeling communicated itself to Wilfrid; for a few seconds he stood, still holding the Princess in his arms, scarcely daring to turn lest he should see at his elbow some awful apparition. CHAPTER XX WILFRID RECEIVES A CHALLENGE When at last Wilfrid _did_ turn his head he beheld a tall masked figure, motionless, silent, watchful; the very Crusader who had glanced angrily at him in the ballroom. Now when one gentleman comes upon another in the act of kissing a lady, politeness suggests immediate retirement on the part of the first. But this was a course the intruder did _not_ take; instead, he kept his ground as if he had come there for no other purpose than to watch the pair, manifestly indifferent as to whether his presence caused embarrassment or not. Wilfrid could have slain him without the least compunction. Here was a lovely princess, clinging to his embrace, listening to his love-avowal, and lo! the charming situation must come to an end—for a time at least—by reason of the new-comer’s clownishness! As he withdrew one arm from the Princess she made a movement as if to flee. “Stay, Princess,” he whispered. “Do not go. You are safe with me. Do you know this man? Who is he?” She seemed too frightened to make reply; she glanced, now to the right and now to the left, along the moonlit terrace, apparently deliberating which way to flee; finally, with a strength born of despair, she suddenly broke away, and before the surprised Wilfrid could stop her, Princess Marie was lost to view among the darkness of the pines. For a moment he hesitated whether to follow or not, but as running off might look like cowardice, he chose to remain, and turned upon the Crusader, with whom he was now doubly angry. The new-comer moved forward from the shadow of the trees, and, with an air of dignity, now stood in the clear moonlight, looking at the other as if requiring from him an explanation of his recent conduct. “Qualifying for the spy service, sir?” Wilfrid asked. “I am told ’tis a remunerative profession.” “In dealing with dishonourable persons,” was the reply, “nice rules of courtesy must be laid aside.” Wilfrid was convinced that the speaker was Ouvaroff, and that, for some reason or other, the Prince was seeking to disguise his voice. It was not so much the voice, however, to which he gave heed as the words. Dishonourable? As Wilfrid recalled the Princess’s sweet face and innocent eyes, still greater grew his anger against the man who thus ventured to charge her with wrong-doing.