Claire sat there, her mind half on her music and half on the extraordinary conduct of her lover. Not that she did not trust him implicitly; but, still, it seemed strange that he should have gone off without explaining the cause of his agitation.

Some one next to her touched her on the elbow and asked a question as to an item on the programme. The question was repeated twice before Claire realized that she would have to pull herself together. She replied quite at random; then she looked about her, and became cognizant of the fact that Padini was still on the stage, bowing his acknowledgments of the thunderous applause which had greeted his magnificent efforts.

Yet a closer glance did not serve to show Claire anything sinister in the artist's personality. He was pale and clean-shaven, palpably very nervous, and yet pleased with the warmth of his reception. Surely there could have been no mystery connected with a man like this.

On the other hand, the marvelous likeness between his playing and the execution in the same piece displayed by Anstruther two nights ago could not possibly be overlooked by any one professing to any musical knowledge at all. Claire hoped that the inevitable encore would produce a repetition of the same piece.

Surely enough, Padini came forward and struck the opening bars of the same rhapsodie. With eyes closed and mind eagerly concentrated on the music, Claire followed every passage with rapt attention. There was no longer any possibility of mistake. The Padini interpretation of the piece was exactly that of Anstruther. Was Anstruther, therefore, a consummate master of his art or a showy humbug or charlatan? Could it have been possible that this new artist had been concealed in the Panton Square library two nights before? But, on the face of it, this was absolutely impossible. Padini had only been in England a little over eight and forty hours, and his first appearance in London had been at a musical "at home" on the same night that Anstruther had played the Nocturne in Panton Square.

Claire was still debating this problem in her mind when Jack returned to his seat. He looked a little pale and shaky, but the grim smile on his face was determined enough. "My dearest girl, I am going to ask you a little favor," Jack whispered. "I hope you won't think it the least rude of me, but I want you to excuse me going back with you. Can't you guess that there is something more than meets the eye here?"

"I should be very blind indeed if I did not," Claire replied. "Jack, what is the meaning of this strange mystery? Either Signor Padini was at our house the other night, or my guardian learned to play that rhapsodie after having had lessons from the man on the platform before us."

"I may be wrong, of course," Jack said, "but I feel pretty sure that I have guessed the problem. That is why I want you to go off by yourself, and leave me to play the detective so far as Padini is concerned. It is not altogether a pleasant job, but I am going to follow that fellow when he leaves the Hall."

So saying, Jack rose from his seat, and Claire obediently followed his example. Once outside, Jack called a cab, and gave the driver his instructions.

"I think that will be all right," he said. "You may expect me to come round after dinner, my darling girl. I hope you are not in the least annoyed with me; but there is danger ahead for you and me, and it is my duty to prevent it at all hazards. I declare if I had not almost forgotten one of the most important things I had to say to you. On no account are you to breathe a word of this afternoon's visit to your guardian. He is not to know that you have been with me or anybody else to the Albert Hall to-day."

Claire glanced at the pale, anxious face of her lover and gave the desired assurance. She felt perfectly safe in his hands; he would tell her all there was to be told in due course; and now for the first time she congratulated herself on the fact that her engagement had been kept a secret from Anstruther.

Meanwhile Jack had returned to the back of the Hall. So far as he could recollect, Padini was down on the programme for no further item that afternoon, therefore it was only a matter of waiting till the violinist emerged, and following him to his destination. But Jack had succeeded in consuming three cigarettes without any sign of the artist rewarding his patience. Taking half-a-crown from his pocket, he crossed the road and proceeded to interview the stage-door keeper.

"Oh, that foreign-looking chap, is it?" the stage-door guardian said. "Signor Somebody or other who plays the fiddle. Why, he's been gone the last ten minutes."

"Gone!" Jack exclaimed, with palpable dismay. "Why, I have been watching most carefully for him the last half-hour. Was he wrapped up or shawled in any way?"

Whilst Jack still stood arguing there a slim young man, with fair moustache turned upwards à la German Emperor, passed and repassed him hurriedly. The stranger passed into a smartly appointed hansom and vanished.

"Well, there's your man," the doorkeeper exclaimed. "He must have forgotten something and returned for it."

Jack muttered his thanks, parted with his half-crown, and went into the roadway thoroughly puzzled. He could not for a moment doubt the word of the doorkeeper, who was naturally an expert in a recognition of faces. As a matter of fact, the man with the turned-up moustache was the same individual who had been so mysteriously concealed in Panton Square, and who had afterwards accompanied the deaf-mute girl to Mr. Carrington's. On the stage Padini had appeared as a slight, slim man, whose face was absolutely devoid of hair.

Jack stood thoughtfully in the middle of the road, wondering what to do next. His first idea was to go at once and look up Rigby. He must have been standing there a great deal longer than he had imagined, for presently he saw the smart hansom return and take its place on the rank. Here was a slice of luck indeed. Jack crossed over and hailed the hansom.

"Here, I want you to drive me to the office of the Planet," he said. "I suppose you know where that is. Do you want to earn an extra half-sovereign?"

"That's the way I was educate............