“Ah, then you know,” said the girl with a queer, hard look that I had never seen in her eyes before.

“That is all I know,” I said, “and I wondered whether you could tell me any more. Is it on account of these forged notes that he is hiding? It certainly looks very like it, and I have no doubt whatever that that will be the view of the police. What does Ruthen say?”

“He hasn’t told me anything, but I remember one queer incident. Once when we were out together he paid for supper with a five-pound note and we were about to go out when the manager of the restaurant came back and declared it to be a forgery. Stanley apologized profusely, and gave the man another in its place, explaining that he had cashed a cheque at his club and they had given it to him with four others. Apparently the others he had were genuine. I did not think much of it at the time—such a thing, of course, might easily have happened—but after what you have told me I don’t know what to believe.”

It was difficult to believe that the young fellow who had married Thelma and for whom I had formed a genuine liking, could be the ally of a gang of bank-note forgers, yet the evidence was becoming overwhelming.

“But I thought you told me Audley was well off,” I said. “Well-to-do people don’t usually descend to dealing in forged notes.”

“He always appeared to be,” was Marigold’s reply, “but possibly that was how he made his money. As a matter of fact I really did not know very much about him. I met him through intimate friends and I suppose I more or less took him for granted. He was quite obviously a gentleman and one can’t enquire closely into the antecedents of every man one meets.”

I wondered whether the girl had in some way stumbled upon the truth. If this were the case, the shock of finding that the man she undoubtedly was beginning to love was involved in such infamous practices as the passing of forged notes would be quite sufficient to explain the strange change Mrs. Powell had noticed and commented on. It was quite clear, from what Mrs. Powell had said, that she had suffered some blow which had utterly upset her. On the other hand, the knowledge that Audley had married Thelma would have been an equally satisfactory explanation.

In answer to a question, Marigold told me she had seen Ruthen at Rector’s Club three nights before and had chatted with him. He had then told her that he was still in search of Stanley and that he had been looking for him in Paris. But, although she had questioned him, he would not tell her his motives.

We went to a revue together and later I saw her into a taxi on her way home. Though I questioned her as closely as I could, and she seemed quite willing to help, she could not, or would not, tell me any more.

I walked home to Russell Square utterly bewildered and spent a sleepless night racking my brain for a solution of the mystery. Here we were in April and so far as I could tell I was as far off as ever from finding the key to the enigma.