Which is why neither Wattis, nor the Queen of England’s great-uncle, ever won an Edgar or a Gold Dagger. Literary ideas, of course, are easily come by-it’s executing them that is hard. Indeed, the more she thought about it, the more the two gentlemen’s cunning plot twist seemed to glow with possibility. But if there was a slightly condescending element of what we might now call “mansplaining” to both suggestions, Christie was not offended. The novelist read the Prince’s flattering letter with a smile, because the idea suggested by the man who would in the 1960s become the “unofficial godfather” of Prince Charles was exactly the same as the one her brother-in-law, James Wattis, had come up with a few months earlier. He then went on to offer her what he thought was a unique and fun idea for a plot. The future Earl Mountbatten, last British Viceroy of India, was a fan of Christie’s work, he explained in his note.

Prince Louis of Battenberg was a fashionable Royal Navy officer and pal of the louche and stylish Prince of Wales (the one who’d abdicate the throne to marry Wallis Simpson).

In the spring of 1924, the young detective writer, Agatha Christie-whose third novel- The Murder on the Links-had been published six months earlier to favorable notices-and even the odd blush-inducing comparison to Sir Arthur Conan Doyle-received a letter from an unexpected source.

The murder of the roger ackroyd