"I recognize your costume," he says, as the British officer seats himself. "How long since you came?" "Only a few moments. I have been waiting for your interview with the lady to end." "Ah!" with an air of abstraction; then, recalling himself: "Do you know the nature of the work required of you?" Under his mask, Van Vernet's face flamed and he bit his lip with vexation. This man in black and scarlet, this aristocrat, addressed him, not as one man to another, but loftily as a king to a subject. But there was no sign of annoyance in his voice as he replied: "Um--I suppose so. Delicate bit of a shadowing, I was told; no particulars given." "There need be no particulars. I will point you out the person to be shadowed. I want you to see her, and be yourself unseen. You are simply to discover,--find out where she goes, who she sees, what she does. Don't disturb yourself about motives; I only want the _facts_." "Ah!" thought Van Vernet; "it's a _she_, then." Aloud, he said: "You have not given the lady's name?" "You would find it out, of course?" "Of course; necessarily." "The lady is my--is Mrs. Warburton, the mistress of the house." "Ah!" thought the detective; "the old Turk wants me to shadow his wife!" By a very natural blunder he had fancied himself in communication with Archibald, instead of Alan, Warburton. "Have you any suspicions? Can you give me any hint upon which to act?" he asked. "I might say this much," ventured Alan, after a moment's hesitation: "The lady has made, I believe, a mercenary marriage and she is hiding something from her husband and friends." "I see," said Vernet. And then, laughing inwardly, he thought: "A case of jealousy!" In a few words Alan Warburton described to Vernet the "Sunlight," costume worn by Leslie, and then they separated, Vernet going, not in search of "Sunlight," but of the Goddess of Liberty. What he found was this: In the almost deserted music room stood the Goddess of Liberty, gazing down into the face of a woman in the robes of Sunlight, and both of them engaged in earnest conversation. He watched them until he saw the Goddess lift the hand of Sunlight with a gesture of graceful reverence, bow over it, and turn away. Then he went back to the place where he had left his patron. He found the object of his quest still seated in the alcove, alone and absorbed in thought. "I beg your pardon for intruding upon your solitude," began the detective hastily, at the same time seating himself close beside Alan; "but there is a _lady_ here whose conduct is, to say the least, mysterious. As a detective, it becomes my duty to look after her a little, to see that she does not leave this house _until I can follow her_." "Well?" with marked indifference in his tone. "If she could be detained," went on Vernet, "by--say, by keeping some one constantly beside her, so that she cannot leave the house without being observed--" Alan Warburton threw back his head.