Considering the possibility of Holmes being related to the Addams Family, probably on Morticia's side for the Frenchness
Primarily based on these images
But also because I want Holmes and Morticia to speak French, and for him to fence with Gomez, and teach the kids about poisons and criminals
(The family all adore Watson and find him absolutely fascinating, of course)
“Here’s a letter for you, old man,” I announced as I sifted through the morning post one grey day in October. “Not a lot else, I’m afraid.”
Holmes folded down the top of the newspaper he was reading so he could see me. “A letter from whom?”
“Not sure.” I turned it over to study it as best I could. The envelope was thick and expensive, postmarked from America. The ink was rich and black, and it smelled unexpectedly floral, with an odd sulphuric note underneath. “Looks to be a woman’s writing, I’d say.”
“If you would.” He held out a pale hand. I passed him the envelope and he neatly sliced it open with his pocket knife. A single page slipped out onto his breakfast plate. He unfolded it with a flick of his wrist, then smiled. “Ah! Morticia.”
“Morticia?”
“Addams. She is my second cousin.”
I was immediately intrigued, for Holmes so rarely talked about his relatives. It had taken several years after our meeting for him to bring up the subject of his elder brother, who lived and worked barely an hour’s walk away. I wasn’t surprised that a second cousin in America had gone unnoted until now.
“Unusual names run in the family, I see.”
Holmes smirked. “Her grandmother was my great-aunt Séraphine, who met and married a quite singular gentleman named Algernon Frump while travelling. They settled over in the States many years ago, and dear Morticia now resides there with her husband.”
“Why does she write you?”
“She is arranging a sort of family reunion on All Hallow’s Eve. Apparently it has been far too long since we have all seen each other.”
“How long is that?”
“Several years at least. It was certainly before you and I met.”
“And will you oblige her?”
“I suppose I will.” He folded the letter and placed it neatly back in its envelope, tucking it into his inside pocket. “You’ve been angling for a holiday, my boy. Would this satisfy you?”
“Wouldn’t it be terribly rude?” I asked, startled. “She has invited you, not me.”
He tutted. “Nonsense, Watson! Morticia knows we live together, of course.”
“How?”
“She will have read your book.”
“Oh! Well that is kind of her. But a family reunion, Holmes, I am not—”
“You are my partner and intimate friend. I assure you there are members of the Addams clan with far more tenuous connections, and many of them also of no blood relation. You will not be out of place, and they will be glad to meet you.”
