As for Westerham, he ran quickly across to the further side of the roadway that he might watch Lady Kathleen's progress to Downing Street, for he was still fearful that she might meet with further molestation. He saw, however, that she reached the corner of the famous little _cul-de-sac_ in safety, and, moreover, that she was saluted by an apparently surprised and startled policeman. As Westerham walked back to Walter's Hotel he was in a most perplexed state of mind. Was it possible that he had stepped suddenly into the midst of some tragic mystery? Was it possible that it was real and actual sorrow and horror that had made the eyes of the girl in the picture—the eyes of the girl who had drawn him back to England—so wistful and so beckoning? That a girl in Lady Kathleen Carfax's position might be suffering some profound grief, or might be the centre of some bit of distressing family history, might well be conceived. But what should take the daughter of the Prime Minister of England to Hyde Park after dark, and what extraordinary combination of inappropriate events could possibly cause her to seek the silence of such a man as he had left insensible? Melun? It was possible that he was connected with the mystery. Westerham now remembered the man's cynical and confident smile when he had so unwisely boasted to him that he proposed to marry Lady Kathleen. If Melun were really implicated in this business, then the methods of his villainy must be far more complicated than Westerham had anticipated. Only a very extraordinary conspiracy indeed could possibly have taken the Prime Minister's daughter into the park at such an hour. From Westerham's own personal experience Melun was a very prince of blackmailers. Indeed, he had not troubled to deny the accusation when Westerham had made it. But even the nimble imagination of Westerham had not foreseen the possibility of blackmailing the Prime Minister, at whose back were all the forces of the law, including a discreet and silent and swiftly-acting Scotland Yard. Westerham sat far into the night, turning all these things over in his mind; and the more he pondered over them the more convinced he became that Melun must be in some way implicated, if indeed he were not the originator of the whole business. It was, however, upon what matter Melun could possibly blackmail Lord Penshurst that caused Westerham the most perplexity. Obviously it was not some minor question of personal honour which involved the necessity of maintaining some sordid and disgraceful secret, or obviously Lord Penshurst's daughter would not be risking her personal safety, and to a great extent her reputation, by making such a visit to the park.