Much surprised, both Lord Barminster and Mr. Shelton accompanied her; and they found the voices were issuing from one of the small anterooms adjoining the terrace.  Within this room, which was far removed from where the dancing was going on, they discovered Adrien Leroy, unmasked and very pale, staring at a blue paper which had evidently been given to him by the man standing at his side—­an inspector of police.

“What is the matter, Adrien?” asked his father, and seeing that Jasper Vermont was also present, he turned his eyes to him inquiringly.  But Jasper seemed wishful to avoid his glance, and only shook his head.

Adrien handed back the blue paper, still without speaking, then turned, as if to address his father, who was looking sternly from one troubled face to the other, while behind him stood Lady Constance and Mortimer Shelton.  But before any one could utter a word, the inspector came forward, and addressing Lord Barminster, said quietly: 

“Sorry, my lord, to have to do this at such a time but I am here in the performance of my duty.  I should be glad if we could go to a more private room, where I could explain to your lordship without your guests being informed of the matter.”

Lord Barminster was about to sharply retort when Shelton, who seemed to realise the seriousness of the affair, touched him lightly on the arm.

“I think, sir,” he said earnestly, “it would be as well to hear what this man has to say quietly, as he suggests.”

Lord Barminster controlled his feelings, recognising the good sense of the suggestion, and turning coldly to the inspector, said: 

“Perhaps it would be best, Inspector.  Kindly come this way.”

At the end of a small passage outside the anteroom, the door opened into a smaller room, which at one time had been used as a study, and was noted for its impenetrability as to sound.  Here they entered; and Lord Barminster, asking all to be seated, bade the inspector proceed with such explanations as he had to offer.

“My lord,” he said respectfully, “the explanation is a very simple one, and in deference to your lordship, to make it as private as possible, I have left my men outside the Castle.  I, unfortunately, hold a warrant for the arrest of Mr. Adrien Leroy on a charge of forgery.”

An exclamation of horror burst from all, except Adrien and Jasper; but the speaker continued: 

“In performance of my duty, I arrest him, in the King’s name.”  He touched Adrien lightly on the arm as he spoke.

Lord Barminster drew a long breath, but still hoping against his better judgment that the affair was what its originators considered, a practical joke, he restrained all appearance of anger.

“Come,” he said, “this may be an excellent jest; but whoever is responsible for it must surely realise that it has gone far enough.”

“This is no jest, sir,” said Adrien, and he looked at Mortimer Shelton, who sat, white and bewildered, opposite to him.