Tuppence nodded cheerfully.
She did not put in an appearance at the office all day. When Tommy returned that evening about half past five it was to find a wildly exultant Tuppence awaiting him.
“I have done it, Tommy. I have solved the mystery of the alibi. We can charge up all these half crowns and ten shilling notes and demand a substantial fee of our own from Mr. Montgomery Jones and he can go right off and collect his girl.”
“What is the solution?” cried Tommy.
“A perfectly simple one,” said Tuppence. “ Twins. ”
“What do you mean?—Twins?”
“Why just that. Of course it is the only solution. I will say you put it into my head last night talking about mothers-in-law, twins, and bottles of beer. I cabled to Australia and got back the information I wanted. Una has a twin sister, Vera, who arrived in England last Monday. That is why she was able to make this bet so spontaneously. She thought it would be a frightful rag on poor Montgomery Jones. The sister went to Torquay and she stayed in London.”
“Do you think she’ll be terribly despondent that she’s lost?” asked Tommy.
“No,” said Tuppence. “I don’t. I gave you my views about that before. She will put all the kudos down to Montgomery Jones. I always think respect for your husband’s abilities should be the foundation of married life.”
“I am glad to have inspired these sentiments in you, Tuppence.”