This time, I received an invitation – or at least I think I did. As I poured out the last of a 2009 Bordeaux, white tartrate crystals at the bottom of the goblet seemed to spell a message on a background of purple dregs: “Pont dA 11 Nov 12am R.”

I blinked and gave the goblet an inebriate second glance, but the wine diamonds had sunk into the slush and the ghostly message had blurred.

“The Pont d’Alma – the entrance to the Paris sewers – at midnight on the 11th of November,” I translated the shorthand that only could have come—the Devil knows how—from the Ghost of Cardinal Richelieu, my ghostly interlocutor on so many past occasions.

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