“ Épatant! ” murmured Poirot. “Without doubt a romance of the first water.” He turned to Mary Marvell. “And you are not afraid, madame? You have no superstitious terrors? You do not fear to introduce these two Siamese twins to each other lest a Chinaman should appear and, hey presto! whisk them both back to China?”

His tone was mocking, but I fancied that an undercurrent of seriousness lay beneath it.

“I don’t believe that Lady Yardly’s diamond is anything like as good a stone as mine,” said Miss Marvell. “Anyway, I’m going to see.”

What more Poirot would have said I do not know, for at that moment the door flew open, and a splendid-looking man strode into the room. From his crisply curling black head, to the tips of his patent-leather boots, he was a hero fit for romance.