Denise replied in the same tone my mother had used then, “Oh yes, when we weren’t hunting dinosaurs for dinner, we played cards. Of course we had them. How old do you think I am?” She smiled and added, “People have been playing cards for centuries, my dear. They’re not a new invention.”

Something struck my memory, hard.

Forgetting all about Luc’s kiss, or that he was still standing close beside me, I excused myself. I crossed from the salon into my workroom, pulled my gloves on, and with care turned back the pages of the diary to its start.

Upon the 22nd came my eldest brother Nicolas… I followed down the neat handwritten lines: Sir Redmond Everard, for so his name is, seemed not in the least put out to have us thus descend upon him. He and his good lady made us welcome… Further down, my finger stopped. I’d found it: Supper being done we then amused ourselves at play upon the cards.

They had been playing cards, perhaps in that same room where Mary Dundas had the next day sat and talked to Mistress Whatever-her-name-was, who had crafted there “upon the spot” a cipher using something close at hand.

I sat, and slipping off the gloves reached for my pencil once again, and started setting down a simple substitution cipher using varied values for a suit of cards. It nearly fit. I tried with aces high and aces low, and padded extra numbers round the real ones, just as numbers had been added in the first test cipher Alistair had given me, for camouflage. It nearly worked. The letters still spelled gibberish, but something in the patterns that they made now gave me hope.

Perhaps, I thought, the fault was mine. Perhaps the cards that Mary had been playing with were different from our modern packs of cards. I turned my chair around so I could use Claudine’s computer, neatly tucked into the corner of the room behind my working desk. A quick search on the Internet bombarded me with facts and speculations on the origins of playing cards, but cross-referencing my sources left me fairly sure our modern packs—with fifty-two cards split into four suits of clubs and diamonds, spades and hearts—had been established by the 1500s here in France, a full two hundred years before Mary Dundas had come along. She wouldn’t have been playing with a joker, since those hadn’t yet been added to the pack, but all the other cards would have matched those I was familiar with. So if cards were the basis of her cipher, all I had to do was figure out which order she had used them in.

Returning to my study of the diary, I stared hard at the three blotted numbers in the margin that appeared to be eight, nine, and ten, as though by staring I might force them to give up their secrets, but they stubbornly stayed blot-like and unhelpful.

All through dinner my mind remained fixed on the puzzle. I failed to appreciate all the fine food that Denise had prepared for this most festive meal at the end of the year. We had champagne and oysters, smoked salmon on toast and roast pork and a platter of delicate cheeses, with wines for each course and a chocolate log cake for the finish, but I didn’t register all of the tastes. And I stayed on the fringe of the talk, only answering when I was spoken to, which to my great relief wasn’t that often.

Claudine and Luc had a discussion about some French folk singer she had once photographed whose name meant nothing to me, so I happily kept out of that, and then Noah was kept busy answering questions about what he’d done with his grandparents, which once again was a topic I wasn’t expected to have an opinion on, leaving my mind free to think about playing cards and how one might work them into a cipher.

I was focused on this when I felt a soft tap on my forehead, and I glanced up as a second something hit me very lightly on my cheekbone. From his seat across the table from me, Luc grinned as he lowered his toy blowpipe with its ammunition of small wads of paper. “You make an easy target when you’re thinking. Denise wants us all to move into the salon. Would you like brandy?”

In the salon, Claudine dimmed the lamps to let the fairy lights and decorations show and shimmer. Opening the doors of a tall cabinet, she revealed a television that I hadn’t known was there, and soon a program called Le Plus Grand Cabaret du Monde—“The Greatest Cabaret Show in the World”—was working hard to entertain us with a dazzling cavalcade of international performers seeking to outdo each other with their acts of song and dance and acrobatics. There was a magician, too, who managed complicated things with scarves that briefly captured Noah’s interest, but when that was done the boy returned his own attention to his handheld gaming console.

“What is that you’re playing?” asked Luc.

“Robo Patrol.”

Denise explained to Luc, “It was a gift from Uncle Thierry.”

“Yes, of course it was. Your brother only gives gifts that make noise.” Luc held his hand to Noah. “Can I have a go?”

Noah shook his head, not looking up from his game. “Uncle Thierry said that it is not for you. He says you are too old to play it.”

“Uncle Thierry is older than I am.”

“He seems a lot younger.”

“Not mentally,” put in Denise, and Luc answered by raising his toy blowpipe, aiming it in her direction and pinging her with a small wad of bright paper.

“Just give me the game.”

Noah handed it over and waited, and smiled when the synthesized music trailed off on a flourish. “You died.”

“I’m only wounded,” said his father, and the music started up again.

Claudine curled into her armchair and said, “Noah, why don’t you show me your new card trick?”