“My dear Louis,” he said, “one-fifth of the mystery is already solved.”

“One-fifth? How do you arrive at that?”

“Because it is one-twenty-five and we started at eleven-thirty.”

He nodded to their waiter, who was standing three tables away, and paid the bill. Then with perfect gravity he permitted Mr Carlyle to lead him by the arm into the street, where their car was waiting, Parkinson already there in attendance.

“Sure I can be of no further use?” asked Carlyle. Carrados had previously indicated that after lunch he would go on alone, but, because he was largely sceptical of the outcome, the professional man felt guiltily that he was deserting. “Say the word?”

Carrados smiled and shook his head. Then he leaned across.

“I am going to the opera house now; then, possibly, to talk to Markham a little. If I have time I must find a man who knows the Straithwaites, and after that I may look up Inspector Beedel if he is at the Yard. That is as far as I can see yet, until I call at Luneburg Mansions. Come round on the third anyway.”

“Dear old chap,” murmured Mr Carlyle, as the car edged its way ahead among the traffic. “Marvellous shots he makes!”

In the meanwhile, at Luneburg Mansions, Mrs Straithwaite had been passing anything but a pleasant day. She had awakened with a headache and an overnight feeling that there was some unpleasantness to be gone on with. That it did not amount to actual fear was due to the enormous self-importance and the incredible ignorance which ruled the butterfly brain of the young society beauty—for in spite of three years’ experience of married life Stephanie Straithwaite was as yet on the enviable side of two and twenty.

Anticipating an early visit from a particularly obnoxious sister-in-law, she had remained in bed until after lunch in order to be able to deny herself with the more conviction. Three journalists who would have afforded her the mild excitement of being interviewed had called and been in turn put off with polite regrets by her husband. The objectionable sister-in-law postponed her visit until the afternoon and for more than an hour Stephanie “suffered agonies.” When the visitor had left and the martyred hostess announced her intention of flying immediately to the consoling society of her own bridge circle, Straithwaite had advised her, with some significance, to wait for a lead. The unhappy lady cast herself bodily down upon a couch and asked whether she was to become a nun. Straithwaite merely shrugged his shoulders and remembered a club engagement. Evidently there was no need for him to become a monk: Stephanie followed him down the hall, arguing and protesting. That was how they came jointly to encounter Carrados at the door.