The inspector’s thoughts raced. Acting on a sudden impulse, he rose, asked his hosts to excuse him and left the table. He came down the stairs just as the dance was ending and the couples were drifting back to their seats. Then a curious incident occurred. Harper’s bow tie, inexpertly tied, had become disarranged, and the ends were hanging loose. The girl, with a laugh, began to tie it for him where they stood within a few feet of the watching detective. It was a pretty sight, but the bow that she had tied was scarcely a thing of beauty. Harper evidently felt that something was wrong and turned to rearrange it in one of the mirrors that flanked the wall. In order to do this, he half turned his back on the inspector, who looking carefully over his shoulder could see his face reflected quite clearly. Their eyes met, and as they did so Mallett saw something that almost made him start. It was the expression on the young man’s face—a fleeting look of mingled fear and horror that he could not have believed possible in that handsome carefree countenance. The whole affair was over in an instant. Harper recovered himself almost at once, the bow was retied to his satisfaction, and he turned again to his partner with a smile. Then the lights were dimmed, the orchestra struck up a waltz, and they were in each other’s arms once more. Mallett remained in the shadows, staring and wondering.

A hand fell on his shoulder.

“Well,” said Lord Bernard’s voice. “If you’re ready, shall we be off?”

“Thanks,” Mallett answered. “I think I’ve seen all I want to here.”

Lord Bernard raised his eyebrows, but said nothing. It was characteristic of him not to ask what the inspector had seen, or why he had left the table so abruptly. Clearly he was a man who could keep his own counsel and respect that of others. Silently he followed his guest out of the hotel and into the waiting car.

“It’s a new experience to have a policeman in the car with me,” said Lord Bernard as they passed the pylons which mark the boundary of Brighton. “Up till now they’ve always been on the other side of the fence, so to speak. D’you mind if I let her out a bit?”